Beach Ball Race- kids work together to hold beach ball between their backs for the first leg of the race, then their sides, then elbows. The field Day Challenge is halfway down on web site & includes water relay, tricycle race, and tug-of-war. Check it out!
Relay Race Tic Tac Toe. You only have 3 items per team (there is never a cats game), so after the 1st three people go, the next people go and move one of their items to a new place. Lots of creative ways to switch this up (create obstacles, 3 legged races, crab walk over to it, etc)