It's hard to top Randy Johnson killing a bird...man that was insane!
http://media.ebaumsworld.com/birdball.mpg
I remember a few years ago, Green Bay was playing and a cornerback (safety?)defending Antonio Freeman looked like he was in the perfect place to just knock a pass down. Instead the ball got tipped around, the corner fell on his ass, the ball twirled around a bit more and Antonio reached down and took the ball off the defenders shoulder pad and ran in for a TD. I'm probably not doing it justice in my description, but that play was amazing.
That's why sports is the ultimate in entertainment, you never know if something truly spectacular is going to happen.