that we used to play
in high school
The basic rule was this: Everytime you said a word that started with the letter B, you had to immediately say "letter B' right after it. For instance, the sentence "I would like a bologna sandwich and a bottle of beer." would become "I would like a bologna letter B sandwich and a bottle letter B of beer letter B." Until you said "letter B" after a word starting with B, everyone around you was allowed to punch you repeatedly until you did. Usually, your best strategy was to avoid saying words that started with the letter B at all, so that you didn't have to remember to say "letter B" all the time. Generally, though, you had to live continually paranoid of what you said and how perceptive the people around you were.
I was good at catching people, but overall I sucked at the game, because if I forgot to say "letter B" myself, and people started pounding on me, I would just keep laughing and not actually say "letter B", and the beatings would continue.
Ah, good times, good times. . .