In one game, I had a bunch of
Cheesy Promotional Bookmarks of Power and distributed them to the other players before the game as I'm the one that buys all the
Munchkin stuff and I don't like using the promo stuff unfairly.
In the game, somebody decided to use theirs, tore it up, recited the text perfectly, giving the tra la las with gusto. Everybody laughed. When he sat down, I pointed out that he had neglected to throw away any of the pieces while doing so and according to rule 4, it means he wasted the bookmark. The look on his face was priceless in that he'd embarrassed himself for no reason, but it was all in good fun.
He also got me back later by using
Trained Moths! to stop me from using a different bookmark in one of his combats, allowing him to win the game, so there was no hard feelings.