Via my dog wants to be on the radio [1] comes this rather fasinating game called 1000 blank white cards. [2] The rules? Well, short of drawing the cards yourself (well, you and the other players) there aren't really any other rules, other than play proceeds clockwise, unless otherwise noted. Something like Nomic [3] with cards, only less rules.
I remember years ago in college (“Uh oh, there he goes again, reminiscencing again!”) my friend Bill and I are in one of the library study rooms trying to kill time between classes (we had a couple of hours). There was a blackboard in this particular study room and fortunately we actually had chalk on us! (And no, we weren't TA (Teaching Assitants)s—I think we had the chalk for use playing pool where we would chalk up part of our hand to help the cue stick slide but I digress). What I don't recall is if we actually had a checker board on us, or drew one but at any rate, somehow we had a checker board and pieces. We started to play a game of checkers, but to make it more interesting, after each move, we would add a new rule to further complicate the game.
The only one I remember is “Kings [in checkers, which we were playing] now move like Queens [like in Chess, which we weren't playing].” We both laughed ourselves silly over that one, but I guess you had to be there at the time to get the full effect. I also remember winning the game since I was able to contrive a set of rules that forced Bill to forgoe a turn, thus loosing the game.
Anyway, it seems that 1000 blank white cards is a similar game—similar in that “we make up the rules as we go along.” And those can be real fun if you have the right mix of people.
[1] http://gweezlebur.com/~ivey/weblog/