I don't think the kid jumping was funny, that was stupid - he deserved to get hurt. Whenever I think of funny plays I think of the ball going off Canseco's head for a homer and the outfielder running through the wall going back for a flyball. There are plenty more, but those two come to mind right away.
I'm not sure if it technically counts as a sports moment, but I'd choose the time the Daryl Strawberry excaped from a court ordered rehab facility then had a friend he was with call the police and say that he was kidnapped.
Either that or the time in little league that all my white underware were dirty so I had to wear bright green ones and they showed through my pants.