Hey Fetor,
That brings back some childhood memories...Were I grew up this guy had a bull, and he was a pretty mean bull, and the "game"

was someone would throw a tennis ball into the field (usually in the bull's vicinity and sometimes hitting him with it) and the challenge was to get the ball and get back over the fence. Well the bull seemed to get more agitated the longer the game went on as you can imagine. There were some twisted ankles and serious splinters from getting back over the fence in a hurry but, nobody ever got really hurt.
