Self-modifying Games Centre

I enjoy loopy things like self-modifying games. I define a self-modifying game as one in which the rules change in such a manner that you can't predict what rules you will be playing with later. Unfortuneately, there don't seem to be very many of them. If you've heard of one not mentioned here, let me know.
Warthog A card game also known as Bartok and Mutant Crazy Eights (thanks to Jed Hartman for this alias). I maintain a rules site for Warthog.
Mao A card game similar to Warthog but much more cruel.
Ascending Rules Uno This card game is based on UNO, but similarly to Warthog and Mao, a new rule is added before each hand. Dealership rotates around the table, and the dealer makes the rule (rather than the winner of the last hand, as in Warthog and Mao).
Big Brother My friends and I invented this game as an exercise in creating self-modifying games. As far as I know, it has been played once. It involves no cards or game pieces of any kind and in some ways resembles Nomic. Warning: It makes players very paranoid.
Nomic Nomic was invented by Peter Suber, and described by Douglas R. Hofstadter in "Metamagical Themas". I've heard of several variations on Nomic, including Micronomic (starts with only two rules), Imperial Nomic and Emporer (has a dictator instead of a committee). There's a Nomic FAQ here, here or here.
Eleusis A card game in which new rules only last for one round.
The Mind Game This game doesn't exist -- it's a computer game described in a fictional novel (Orson Scott Card's "Ender's Game"). The computer game responds to the desires and needs of the player and creates a fantasy world with puzzles that have deep moral and psychological implications. Anyone want to try programming this? By the way, I highly recommend the book, even if you're not a science-fiction fan. The science is good, but the characters are better.
Calvin-ball Everybody knows how to play Calvin-ball. There are no rules for how to add rules to Calvin ball -- it depends on how loud you are, how well you can bully other kids, and what happens during the game that you don't like and want to make rules against.
MUDs and MUSHes I count MUDs and MUSHs to be among the self-modifying games because, especially in MUSHs, it is possible for the "player" to add rooms to the world for other "players" to explore. Also, items and "monsters" can be added. However, it is not a good example because the rules of the game do not change. I'm interested in games which are fundamentally different after you play them for a while, not just games which have different stuff in them.
Ego-mania I've heard about this board game from Peter Duniho, but never seen it or played it. Here's Peter's description:

"It's a board game, with about a half-dozen special areas on the board, and concentric-circle maze type paths connecting the various areas. Generally, the goal is to gain money, or power (with the assumption that you could get one, given enough of the other :) ). During game play, cards are pulled from a couple of decks. Either deck affects game play, but one deck in particular has a bunch of cards which radically shift the game play or state of the game. For example, some cards involve swapping control of board pieces, money, decision-making, etc. or some combination of those elements (eg, a card might allow one player to control the movement of another player's game piece...the other player still decides what to do upon arriving at a board location, but the one player decides where, given the roll of the dice, that other player moves to); some actually involve a complete shift of all players, or of a pair of players. Some alter the goals of the game...there's usually some element of the game that can return the state of the game to more relative normalcy, but you can win by achieving the new goals before that happens."

"Egomania's objective is to become the Supreme Ego by amassing the required amount of powers and properties. This is accomplished through the use of: owning powers, owning properties, target cards, altered states, and scenario cards. Any or all of these cards allow each player to: negotiate, strategize, or influence the flow of the game."

Game is for 3-4 players, ages 15 or older.

Nightmare Chess Ever had the desire to change the rules of chess just to see what would happen? Probably not. Well, if you have, or if I've made you curious, Nightmare Chess is a commercial game which helps you do just that. Using a standard chess set with some markers (to mark pieces which gain special attributes) and the Nightmare set of cards, two players take turns making chess moves and playing cards which change the rules of the game. It can get pretty silly.
Cosmic Encounter Another contribution from Peter Duniho.

"It's an "alien space conquest" type game. As the game progresses, various cards grant each space alien race (one race <--> one player) different powers, abilities, rights, etc. "

Fluxx John McLeod, who maintains a site on card games, told me about this commercial card game in which the rules are written on the cards themselves and come into effect as you play them.

If you're new to self-modifying games, I recommend you try Warthog first. It's similar to Mao but a quite a bit more gentle.

Lisa Lippert (to home-page)