Little magic items that charm or entrap the user. For example, a little puzzle, made of wood and wire, that you're supposed to manipulate into some particular shape (you know the kind - even a Rubik's Cube, maybe!): if the owner fails a save, he/she becomes enraptured by it, and won't put it down. If it's finally forcibly taken away, they'll react violently for a couple of turns. Or one of them little kaleidoscope tubes: if the person doesn't save, they'll continue to stare through it and giggle. If it's taken away, same reaction as above.