Here is an idea for a bluffing game, one so simple that I could never market it in its basic form, and indeed would be surprised if I turned out to be the first to have come up with it. The basic idea is to guess how many chips your opponent is going to commit to the pot. He’d like to invest as little as possible, but if you guess correctly, you win, whereas if you’re wrong, now you must bet and he gets a guess.