Snowball Fight...kids write 3 things about themselves on a sheet of white paper. They do not write their names on the paper. Wad it up and on your command, have a "snowball" (or baseball) fight. At the end of 1 minute, each student grabs the nearest snowball and tries to guess who wrote it. Teambuilding... I did this last year, and at the end of the year kids still listed it as a favorite memory!