LORELAI: Rory, you have to do something bad when Mommy’s out of town … . how about a floating craps game or something?
Craps is a dice game where players wage bets based on the outcome of rolling a pair of dice. A “floating craps game” is an illegal operation, so called because operators use portable tables and equipment to quickly move the game’s location, thus staying ahead of legal authorities. The 1950 musical Guys and Dolls features a floating craps game.
The Annotated Gilmore Girls 