my crew always yells out "CHU-POW" when we punch people.
we also like to get high up on buildings and jump down onto the top of people and punch them, while yelling "oooooooooh YEEEEEEEEEAH!" like the macho man randy savage.
another fun one is rushing into a room of enemies with a shotgun, blasting the first one point blank, jumping over the second ones head while shooting him from above, and then smacking the closest one with the shotgun. we call that one Optimus Priming a Room. example "ok, theres two of us and 4 of them, you Optimus Prime the room and ill come in on cleanup" works every time.
one time on halo 3 beta, i was playing high ground and started at the beach. i got to the gate and went up the right rubble wall, and met a guy on the bridge over the gate. i sticky grenaded him, and the explosion launched him straight up, wherein his head went through the roof of the bridge and he stuck there, body dangling all limp. after that we all took turns punching his dead body. it was like that scene from Rocky where hes punching sides of beef in the packing plant. the body just kept flopping around, but his head would not unstick.
i actually recorded it, unfortunately i cant watch them since the beta expired.
we regularly try doing flips and tricks with the ghost, mostly on blood gulch/coagulation.