[Helm]

an early one that left and impression was playing quakeworld and everybody jumping on the head of one guy and then running around like a big human stick. I know it doesn't sound too cool today but back then it was novel that you were playing online even so I guess...

another one was back in UT in this map called fractal that has this trap under the shield belt that seems like certain death, but we played that map so much that we learnt to evade the trap and even use it to our tactical advantage ( it's a hole on the floor level that teleports above the paying area right over a 'laser' or something). It was cool to see other people go 'lol' when you fell into the trap on your own and then teleport above them and sink 6 rockets on their head.

I guess finishing A.D.O.M is also one of the cool videogame moments. Finishing Rings of Power, also after having the game for the last 10 years.