House rules

House Rules are typically a set of nonstandard game rulings used by a roleplaying group in their sessions. This is often to fix some perceived flaw in the standard rules; for example, a group playing a 3e game may increase the difficulty class of Diplomacy skill checks. However, they can just as often serve merely to make a game more interesting or different in some manner; for example, a DM could declare that in his setting, magic is inherently unstable, and there is always a small percentile chance of a spell going awry.

House rules can also literally refer to the OOC rules of the host's house or the DM's game, such as "bring food with you so we don't have to fuck off to Tesco half-way through the game", "if you spill shit on my carpet you will clean it up" and "blowjobs are worth 500 XP".