At the assisted living center where I now reside, one of the other inmates, er, I mean residents, told me he used to coach his son when his kid was in a grammar school age rec league. He said he used to hear a lot of funny things during games but his favorite was when a foul was called on a 4th grade boy. The boy turned around towards the ref and said in a rather loud voice, "YOU'RE A POO-POO HEAD!" The ref laughed so much he didn't take any further action.
I'd really have to think long and hard to come up with the single funniest comment I ever heard during a game. What about you guys (and gals)?