idk, i laughed often times while playing online with friends, but i didn't remember a good one now, only this:

It was my first glitching on COD4, a friend invite me to crossfire, and an another gamer was going in the air, where u can go on the roofs @ the end of the map. There u need to go over the barbwire. I stand below and i saw him walking in the air, and in this moment he was singing "I'm walking on sunshine", we all laughed good.

on mgo, i shot someone in the head and he shot me in the head so we both died at the same time
this happened 4 more times with the same person