This kind of thing is something that people might expect to see at an elementary or middle school basketball game, but never in a professional NBA game.  It really was unexpected, which only made it more hilarious.

Vince Carter got past his defender and had the open lane...he was on target soaring through the air at the basket...the ball rolled off his finger tips for the easy finger roll layup and...what?

You've got to check this out.  Vince could not help but laugh at his failed finger roll attempt.