Much of this was taken from a Google Doc that I wrote for my players. In a coincidence of fortunate timing, this has given me a chance to re-write parts of it to reflect changes in my approach. For example, Filth didn't exist until recently (and was going to get its own post once I had seen how it actually worked, so consider it a sneak peak I guess).
You can sort of tell what was written when based on the font, because Blogger is strange. (or you could use context you animals)
Also, for notes, Notes: are my general musings, Side Notes: are for the benefit of you who aren't playing in this game and so have missed the rest of the context for the house rules and sub-systems. For my hindsightful thoughts, they are right at the bottom.
[Also also, sorry for the terrible formatting. Much of this was taken from a google doc, as I said before. It would not play nice when I tried to cut and paste it. I have just pasted it as plain text for now. I will do nicer formatting later. Its late. I am tired. I am annoyed. Good night.]
Downtime
When you recover, you have 7 days of downtime. For ease, we will codify it into a bit of a procedure.
When you recover, apart from all the health benefits its provides, you also follow the following procedure:
You expend Gold based on your Lifestyle
You test against your Filth
You roll a Lifestyle Event
You choose a Daytime Action
You choose an Evening Action
Lifestyles
There are five ranks, in order of expense spared:
Squalid
You are basically living rough, its free basically.
When you recover, you regain only half your hit die, and at the end of the recovery, you roll all your hit die and add your con mod to each rolled dice. If the result is less than your usual HP max, it becomes your HP max until you next recover.
Poor
What the serfs have to deal with, costs 5gp per week.
When you recover, you only regain half your hit die, otherwise it works as normal
Comfortable
The middle of the road. Recovery is as normal, but this is where it starts to cost a little bit. 25gp per week.
Lavish
You splash out, have a few servants, its a nice place. 100gp per week.
When you recover, you may roll your hit die, and add your con mod as per the usual for hp, if the total is higher than your usual max, you make that your new max until you next recover.
Royal
You spare no expense. Crippling to most nobles even. 300gp per week.
Recovery as per Lavish, and you gain half your prof mod (rounding down) in bonus Hit Die to take down with you.
[Side Note: There are also three classes of district you can live in, Lower, Middle, and Upper. Lower class limits you to the bottom three lifestyles, Upper limits you to the top three, and Middle restricts you to the middle three.]
Lifestyle Events
When you recover, depending on where you live, and the level of lifestyle you have, you will receive a Lifestyle Event; such as being robbed, meeting a peculiar NPC, or finding a particularly useful specialist Vendor.
To do this, roll a d12 and a d20. The d12 indicates your event, and the d20 develops it.
If you live in a Low Class District, roll the d12 with disadvantage.
If you live in a High Class District, roll the d12 with advantage.
The d12 result is taken from the table below. The d20 result comes from the DM.
1 - Robbed!
2 - Made a Rival
3 - A Find on the Black Market
4 - Met an Odd NPC
5 - Receive a Quest!
6 - Receive a Rumour
7 - District Class Bonus
8 - Receive an Omen
9 - Met a Superior Specialist
10 - A Find at the Auction
11 - Make an Ally
12 - Economic Opportunity
For Lower class districts, the bonus result is Robbery.
For Middle class districts, the bonus result is Superior Specialist.
For Upper class districts, the bonus result is Economic Opportunity.
[Note: I will add a bit more of a detailed description for the d12s, but at this point these options are all known factors. It used to be more complex, but I've stripped it down to make this bit run smoother, as I felt this was the real speed-bump previously.]
[Side Note: This is where I learned the truth of the axiom "If you have two rolls, try and make it one." or something to that effect at least. The constant back-and-forth of "what did you roll?, that means this, roll again, what did you get? that means this..." took ages, and wasn't particularly interesting until right at the end. This at least means that more of it is player-facing so that it can move quicker. Sometimes, crunch is fun. Too much crunch is never fun.]
Filth
You accumulate Filth down in the Undercity, slowly simply by being there, quickly by messing around with poop and such. Monsters might inflict you with it. By itself, it doesn't do much, but when you next recover, you must make a Constitution Saving Throw with a DC = Your Filth. If you succeed, you suffer no consequences. If you fail, you catch a disease. If you fail a Filth save whilst afflicted with a disease, it gets worse.
Resting only gets rid of half your Filth, rounding down.
[Note: The Cure Disease spell now works slightly differently. There are two spells;
Suppress Disease: A 2nd level spell that removes all Filth from its target. Gains another target for every 2 spell levels higher you cast it at.
Cure Disease: A 5th level spell that cures a disease. Cures an additional disease for each spell level higher you cast it at.]
[Side Note: My game is in 5th Edition DnD, and has a level cap of 7. This means that the highest spell level you can (naturally) get is 4. To get higher than that, you must transcend your mortal limits, or huff hecking tonnes of Wizard Drugs. Its a cruel world.]
Downtime Actions
When you Recover, you get two special actions; the Daytime Action, and the Evening Action; which represent what you spend the majority of your time during the week.
In general, Daytime and Evening actions can do mostly the same thing, but the Daytime Action represents a more substantial contribution of time.
For certain actions, only one type of action can be used.
For others, you gain an additional bonus for using both your Daytime and your Evening Action for the same Recovery period, called the Combo.
Downtime Actions
These are the more general list, it is not necessarily exhaustive or limiting.
Carouse
(Evenings only)
In essence, blow your money on wild parties, get hilariously drunk, get XP for it.
When you use your Evening Action to Carouse, you spend an amount of Gold of your choosing (at least, initially) and make a Wisdom Saving Throw.
If you succeed, you spend only that much, and get a random Carousing Event.
If you fail, you spend an additional d% of your initial spend, and get an even more random Carousing Event.
In general, it is much more flukey than Philanthropy.
In the end, you gain XP equal to d6 x 10% of the total gold spent.
Don’t spend more than you have. You’ll regret it.
[Note: In classic fashion, 1gp recovered from the sewers = 1xp when taken back to town. Carousing (and Philanthropy, see below) is essentially a way to get bonus bang for your buck. And extra XP.
Commune
Pray to various gods, give some dosh to the poor maybe, sing a few psalms, whatever.
Gain blessing from the Gods, depending on your favour with them.
If you used a Daytime Action: The Blessing lasts until you next Commune.
If you used an Evening Action: The Blessing lasts until your next Recovery.
Communing has no special Combo effect.
[Note: I have yet to actually figure this one out. Thankfully, no one has really wanted to do it so I've just let it lie fallow in the mud. Poor Commune, I should treat it better.]
Condition
Train your feeble body to the VERY PEAK OF PHYSICAL CONDITION.
When you Condition, you may roll your Hit Dice and add your Constitution Modifier to each result, as if rolling for Hit Points. If your total is more than your usual Hit Point Maximum, then the new total becomes your Hit Point Maximum.
If you used a Daytime Action: You roll an additional number of Hit Die equal to your Proficiency Modifier, and discard that many die of your choice after rolling.
If you used an Evening Action: You roll your Hit Die as above.
If you Combo them: You roll an additional number of Hit Die equal to your Proficiency Modifier, and discard that many die of your choice after rolling. You also treat your Constitution Modifier as 0 if it is negative, or 1 higher if it is 0 or positive.
Craft
You get to make a thing! Hooray!
You may only craft with a Tool Set with which you have at least one “rank” of proficiency with.
Crafting adds a certain amount of progress to a project; 2 for initiate items, 4 for journeyman items, and 8 for masterwork items.
You must also have a minimum number of ranks of proficiency with your tools to make items; one rank for initiate, two ranks for journeyman, and three for masterwork.
For each point of progress you make, you must spend gold equal to 5% of the item’s market cost.
If you used a Daytime Action: You make 2 progress.
If you used an Evening Action: You make 1 progress progress.
If you Combo them: You make 3 progress for the price of 2 progress.
[Tiers of quality (initiate -> journeyman -> masterwork exist mainly as a money sink to get incrementally better die sizes for your weapons, or increase the maximum proficiency bonus you can get with tool kits.]
Investigate Item
You will presumably find some strange stuff down there in the sewers; here’s how you find out what the heck it does.
Items have a number of Facts about them:
Their Market Cost
Items they are a key component of
Major Properties (which can be leveraged for making new items)
Who is interested in them (potentially)
Any other Obscure Uses
If you used a Daytime Action: You learn a Fact of your choice.
If you used an Evening Action: You learn a random Fact of the DM's choice (or whatever he can think of first).
If you Combo them: You learn two Facts of your choice.
Mingle
Spread your time among the Taverns, the Salons, the Market Places, and hear what there is to hear.
This is a chance to gain extra Rumours about the Undercity. The more time you spend on Mingling, the more specific or numerous rumours you learn.
Topics of Rumours are:
Challenges you can face
Treasures you can find
Mysteries you can solve
If you learn about a rumour you have already heard, you will receive more specific information about it, so don’t worry about rolling rumours you’ve already heard.
If you used a Daytime Action: You may either choose the Topic of Rumour you learn about, you may learn a rumour of a specific area of the sewers, or you may learn two random rumours.
If you used an Evening Action: You learn a random Rumour.
If you Combo them: You learn a rumour of a specific area of the sewers, and you may choose its topic.
[Side Note: Woe is me and my Rumours.]
Philanthropy
Spend your money on worthwhile and virtuous things, and get XP for it. Essentially a safer version of Carousing.
Choose an amount of Gold, and gain an amount of XP equal to (d3+1) x 10% of what you spent. There are no other rolls, or saves, or anything.
If you used a Daytime Action: You perform the action as above, but you may roll the d3 twice, and choose the better result.
If you used an Evening Action: You perform the action as above.
Philanthropy has no special Combo effect.
Rest
If you have received a particularly dire wound or vicious disease, you may rest exclusively to help you resist their effects.
When you would take a saving throw for a Lingering Wound (such as from being Crippled) or to resist the effects of a Disease, you immediately make a saving throw, with no negative effects for failing it.
You also cure any Filth you may have.
If you used a Daytime Action: You make a Saving Throw with Advantage.
If you used an Evening Action: You make a normal Saving Throw.
If you Combo them: You make both this Saving Throw, and the subsequent Saving Throw against this malady with Advantage.
[Note: This one needs a bit of re-working with Filth, and also the fact that no-one ever gets wounded. But maybe that's just 5e.]
[Side Note: Crippled comes from my experimental replacement for death saves. When you hit 0, you pick one of being Unconscious, Crippled, or Dying. Unconscious means your out of the fight, even when healed. Crippled means you do everything at disadvantage basically. Dying means you must Con save each turn or die. If you are hit while at 0, pick another thing. All three is instant death (if you even make it that far). It might be a bit kinder than normal really, but its also more interesting most of the time. The only problem is that in 5e, its actually literally impossible to hurt characters.]
Retrain
Did you hastily pick a class feature? Do you regret it slightly? Do you think a different one would be more useful for where you plan on going next? Why not Retrain!?
If you used a Daytime Action: You may choose a different option for two different Class Feature which tells you to choose from a list of options; or the same such Class Feature twice; such as Fighting Styles, Expertise, Favoured Enemy, etc.
If you used an Evening Action: You may choose a different option for a Class Feature which tells you to choose from a list of options, such as Fighting Styles, Expertise, Favoured Enemy, etc.
Retraining has no special Combo effect.
Study
Use this to learn, or copy spells.
If you used a Daytime Action: You may copy a number of spell levels into a book equal to double your level, or you may learn up to three new spells and add them to your spellbook.
If you used an Evening Action: You may copy a number of spell levels into a book equal to your level, or you may learn a new spell and add it to your spellbook.
Studying has no special Combo effect.
[Side Note: Learning new spells from scratch is much harder than copying spells from a spell-book, unlike in 5e (irc, at least).]
Train
Use this to learn, or improve, skill proficiencies.
There are three effective “ranks” of a skill; Half Proficiency; Full Proficiency; Double Proficiency.
To improve a skill, you must roll a d20, with a result equal to or less than:
your intelligence score - the number of skills/tools/weapons you are proficient (or better) with.
Use the type of proficiency that is most applicable.
If the roll is successful, you improve your proficiency by one rank (or become proficient with the weapon group).
If the roll is unsuccessful, you may put a checkmark next to the skill. If you Train a skill which has more check marks than ranks, you automatically succeed on the roll to Train it.
If you used a Daytime Action: You may attempt to improve a skill that you have at most one rank in.
If you used an Evening Action: You may attempt to improve a skill that you have no ranks in.
If you Combo them: You may attempt to improve a skill that you have at most two ranks in.
[Side Note: I think its pretty good. It works for the megadungeon/west-marchy thing where the adventure isn't in town. It would be easy enough to change for a game where the average downtime period is a day too if you wanted. Its still a bit crunchy for me, but I think that's just slightly representative of playing 5e. It works enough at making the Downtime thing fun to do, without giving it the scope to spread too out of control. It wouldn't suit every game for sure, and I think you could parse it down to something suitable for every game. Eventually I may even do just that.]