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.
It doesn't really help with mistakes, since the 'reader' pauses, stops, starts, and just generally uses whatever tone it wants to, regardless of your punctuation... BUT, that said... it's really funny to listen to :D hehe