Fun Fact: If you name your team "TERMINATOR" all of your robot players will have laser swords.
Take baseball, substitute robots for the players, allow them to beat the ever-living crap out of each other and you have the basis for Base Wars locked down. It had all the trappings of other baseball games like stats and rosters, but added things like weapon upgrades into the mix.
That was the only problem with Base Wars – you could win in the single-player mode by bringing one of your robots with a flying-saucer body up to the plate, just putting the ball into play, and then bashing up and down on the basebots to score runs. It was much more challenging to actually play the game correctly, but winning through player attribution was too damned funny not to try over and over again.