My brother David reminds me of a game we used to play when we were kids: Crash. Here are the rules of the game as he describes them ... believe it or not, they are quite accurate. I'd only add that the playing field was more often than not the driveway, which was on a short hill at our house ... we would often start the game at the top of the driveway, one on each side, and then ... well, here are his rules:
HOW TO PLAY
Equipment needed - 2 tricycles (preferably your sisters')
1. Each player runs into the other at full speed on the trike
2. Play continues until a bone or trike is broken or when your sister wants her tricycle back (or mom calls you in for dinner).