As the kids enter the classroom, pass out a roll of toilet paper and casually tell them to take as much as they like. Take some yourself. Lots of snickering goes on, after all it's TOILET PAPER!
When everyone in the class has some, tell them for each square they took they have to tell one fact about themselves. Start by modeling your own introduction by using your squares.
This can get hilarious, depending on how many squares each student took. A great icebreaker for the first day of school!