cupsanddowns is a game where one team tries to turn all the cups upside down and the other team tries to turn them right side up. At the end of the time, whoever has the most their way wins. Simple, inexpensive game that could bring a lot of energy.
You only have 3 items per team so after the 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.