You'd wind up your top, pull the string, and sit back and watch the fun. The last top left spinning was the winner!
You had four tops in each corner of the plastic arena and you pulled the string on your top. they spun around and knocked each other down. The last top spinning won.
It was a game played in a blue plastic "arena" and each player picked a top. The tops each had different names. I don't remember how you got the tops spinning but the last one remaining wins.