I desinged games for fun when I was in college. The one I thought worked best was an evolution game (I majored in Geology.) You had a choice of being a Mammoth, a Saber Tooth Tiger, a Stegosaurus, and one other animal I've since forgotten. Each animal had it's own adaptations for a particularl environment, and there were environment cards which changed when someone landed on an Environment card space. You moved by drawing from you gene pool. Depending on what the environment was, you either moved forward (thick wool on a mammoth when it was an Ice age or backward if it was a tropical environment.) If you got stuck in the wrong environment too long, you kept going backward until you went off the board and went extinct. If you were in a favorable environment, you kept moving forward and the first player to reach the acme of evolution won. There were four different environments, each one most favorable to a particular animal. My nephews thought it was pretty cool, but not as good as the mountain climbing game I designed, where the dirtier you played ( partially severing your opponents ropes, or loosening the pitons) the better chance you had to win. None of my nephews because of my bad influence..:-)

Jerry