Could you get a special photo for each of them made into a small gift like a keyring, maybe with a small inscription on the back with the date as a nice memory.
Some kind of game could be another idea - with cards with some kind of charades on or trivia - maybe even trivia about each other or questions about things to share.
Going a bit further, a surprise mini murder mystery type game for after could be an idea with props in the gift like a fake moustache, glasses etc... to make up a character.