One of my favourite things about reading other people's D&D experiences on the internet is hearing all of their house rules. No two D&D games are alike, and house rules are one of the ways GMs can customize their game to fit their own needs and play styles. I myself have picked up a number of house rules from the GMs I have played under, from the tales people tell on the web, and from my own imagination. For your convenience (and mine), I will be compiling all of my house rules right here on this page.
I hope you find it interesting, and just maybe you'll steal one or two for your own home game. I'll keep this updated with new house rules as they spring into existence.
Absent players' characters gain half the XP that the other characters gain, not including individual XP rewards. The characters are assumed to be off on their own lesser adventures.
This is my favourite house rule yet because it helps absent players keep up with the group but still rewards the players who show up. Now, missing a few sessions doesn't leave you with a hopelessly underpowered character. I first used this rule in my recent(ish) sandbox campaign, where I had a large number of players, many of whom were not able to show up to every session.
Foraging for Food
The base Survival skill check for getting along in the wild (moving up to half your speed while gathering enough food and water for yourself) is DC 15.
As written, the DC is 10, which I think is way too low. Why have rules for hunger and thirst if you're never going to use them? Well, just in general skill check DCs are too low to stay interesting at even moderate levels. But as I tend to focus on survival aspects of roleplaying, this is the main one I've addressed. The DC can be further modified based on the terrain; it's a lot harder to find food and water in a desert than in a jungle.
A full night's rest heals one quarter of a character's total hit points.
This is the natural healing rule I have in place right now, replacing the '1 HP per HD' rule which is more realistic but slows the game down. As a player, I don't want to sleep for a full day in a dungeon, and as a GM I don't want to come up with an excuse for why my sleeping players aren't all murdered by monsters (or at least having their sleep constantly interrupted).
This rule is purely a placeholder; I'm trying to work one up based on Hit Dice and Constitution, since those are the things your HP is derived from in the first place, but for now, I'm just using this one combined with the below rule:
Once per day (plus an additional time per every 5 character levels), a player can take an hour's rest and regain 1HD + Con hit points.
This rule is a heavily modified version of 4th Edition's 'Healing Surge' mechanic, but taken way down in power because that mechanic is ridiculous. I wanted a way for characters to regain a little bit of juice to continue on in the dungeon, without making clerics and natural rest obsolete. Again, this is a placeholder rule until I come up with something better.
Whenever you roll a Hit Die while leveling up your character, the GM will also roll in secret behind the screen. If you don't like your result, you can take the GM's mystery result and hope that it's better.
I stole this rule from my first full-time GM, Marc; I don't know where he got it from. I really like it because it gives you a second chance to get a better roll, but there's that sense of mystery about what the GM has rolled. You aren't guaranteed a better roll. Once I was leveling up a barbarian and I rolled a 2 on a d12. Naturally, I took the GM's roll, and it turned out he had rolled a 1. But in general, this gives you a better chance of getting a more powerful character, and more powerful characters mean that the GM can throw more interesting monsters at you. I also like that it give the GM another dice-related power that only adds to the GM mystique.
Alternate rule: Whenever you roll a Hit Die while leveling up your character, re-roll if you get a 1 or a 2 (only for 1s on a d4 Hit Die).
This was the rule I used before stealing Marc's Hit Dice rule. I was playing D&D 3.5 at the time, where wizards have d4 Hit Die instead of Pathfinder's d6, hence the bit about d4s. This rule is nice because it guarantees you won't suffer from a crappy Hit Die roll, but it lacks the mystery and tension of the above rule.
My expanded language rules are available here. I really suggest you use them, because they are awesome. Plus, they are supported by my improved character sheet.
At character creation, every character rolls a Hit Die and adds their Intelligence bonus to determine how many weapons they can choose from their class list to be proficient in. All other weapons on the class list can be used untrained with a -2 penalty instead of a -4. After spending one level's worth of time using that weapon regularly, they become proficient in it without having to spend a feat. All weapons outside of the class list require a feat to learn. Multiclassing expands the number of weapons in the class list, but does not entitle the character to another Hit Die roll.
This rule, based loosely on 2nd Edition AD&D's Weapon Proficiency rules, is designed to make weapon use more realistic: the idea that someone could be proficient with all simple and martial weapons is ridiculous. This rule gives you enough weapon proficiencies to get by, and gives you the opportunity to master more weapons with relative ease. Also, since this is a Hit Die roll, feel free to apply the 'secret GM roll behind the screen' rule as well. And it works well with my improved character sheet, which has a separate section for weapon proficiencies.
I thought it was important to find a way to ensure high-Intelligence characters were rewarded with more weapon proficiencies, without making it so that the average wizard knows more about weapons than the average fighter. I think I struck a pretty good balance, but this rule has not yet been thoroughly playtested (as always, feel free to leave feedback in the comments!). I really like this rule though, and I'm likely to come back to it soon and write up some Traits and Feats to complement it.
This is a living document, and I'll keep it updated with new house rules when I formulate/implement them. If you have any cool house rules that you like to use, post 'em up in the comments!
-your homebrewed d20 despot