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.
I love activities like this for multiple purposes. Anxiety - talk about worries/Coping/Negative thoughts and shoot a marshmallow. Anger - talk about what makes you angry, talk about what you can do to calm your body, etc. and shoot a marshmallow...the list goes on and on plus how cool is shooting marshmallows :).