We did this on Thursdays in the summer back when we all went to work. We'd push an office cart around with ice cream bars and stuff in it and charge a dollar. Any proceeds went to local charities like the soup kitchen, or women's shelter or something nearby in LP City. We had little cardboard clip-ons for the cart so it looked like an ice cream truck and played goofy music. Everyone loved it. It was a little bit of a PITA for us coordinators, but making it seasonal helped keep it from being something taxing.