I've got a framework for the start of a Nomic-like game... it could get quite insane!
Start out with a deck of X cards, where X is 15 times the number of players. If this exact group of players has played before, use the deck that they had last.
- Rules may be changed only by cards.
- The standard method of playing is "Draw One Card, Play One Card."
When a card is played, it's effect is immediately done, then discarded, UNLESS
- The card is labeled as a "Standing One," which means that it remains on the table;
- The card is blank. If a blank card is played, then the player of the card writes anything he/she wants on it. The card is then shuffled into the deck.
- If a card has no instructions, it is played to the table.
- Get 100 points to win.
- Everyone is dealt 5 cards at the start.
- If a player does not wish to play and has less than seven cards, nothing happens- the player loses his turn.
- If a player does not wish to play and has more than 7 cards, s/he must discard one before play passes.
- If a player believes that there are no blank cards in the deck, then all other players must search the deck or their hands for a blank. If there is a blank, the person who said there wasn't loses 10 points and play continues. If nobody can find a blank, then Z cards are added to the deck, where Z is three times the number of players.
Very simple, and slow at the start. Then more than half of the cards are labeled...
"Ha! Play reverses!"
"Yeah well... I have 17 slugs and you only have two, so I have the advantage."
"Oh well..."
"Hey! A blank! Yes!"
"Whoo... that will make play a mess..."
"I'm going to spend 5 slugs and add one blank card to my hand, as this table card says."
"Oh man... wait! This card lets me cut into play- play out of turn. All table cards of yours are given to me because you were about to use them!"
"Let me see that!"
"153.67 points! I win!"
Rule changes, card ideas, etc.. would be appreciated...
By SmartGamer
Lifted shamelessly from the 
Nomic Bulletin Board
I wrote it there, so it's fair