This is just a fun tournament of the Rock-Paper-Scissors game. This is taken from http://www.boyscouttrail.com/content/activity/evolution-1605.asp
All scouts start out as an Egg and try to evolve into a Butterfly by winning games.
Eggs crawl on their knees.
Larva crouch down and wriggle as they walk.
Pupa stand up, but must hop with their feet together.
Butterflies raise their arms up and down.
To play, you find another player at your same level and challenge him.
If you win, you move up a level and he moves down a level. If you tie, you stay the same level and look for someone else to play against.
Over time, some scouts will evolve all the way to Butterflies. If a Butterfly beats another butterfly, the winner has completely evolved and moves to the side of the playing area. Eventually, there should be one scout left at each level and the rest are evolved. It usually works best to call 'TIME!' when about half the players are out so they don't get bored just watching. Or, you can allow butterflies to continue playing and drop back to pupa if they lose.
If eggs to butterflies is too tame, you could use any sequence of things to evolve. We once used worm, chicken, fox, Elvis, Zeus - they had nothing in common, but the actions were fun.