I was watching my friend play oblivion, and we came across the one guy who says "I dont know you, and I dont care to know you". We tried several times to get him to talk to us, but he wouldnt. We came back later to find him just walking around, when someone came up to him to have those dumb NPC-NPC conversations. What made it hilarious, though, is that the person trying to talk to him was an old lady asking about his day, and he just stood there SHOUTING at the top of his lungs over and over "I DONT KNOW YOU AND I DONT CARE TO KNOW YOU!!!", yelling over her as she tried to tell him about her daughter or some stupid thing. Ah man, we just laughed and laughed. To this day, that's still a catchphrase of mine...
Another few happened when I was playing CoD4:
I was playing online and my controller gave out mid-game, so I used the last bit of battery to get my guy prone in some shadows over by a spawn point. I ran over to plug in my controller's charge cord, resigned to getting shot. I was playing as marines, so my guy matched the tan color of the ground, and some dude stood on my body while fighting off my teammates. All they must have seen is him just randomly dying and me getting up off the ground.
I was playing offline with my little brother and I was experimenting with going prone in random areas of the map trying to camouflage myself amoung rubble and grass. We were playing backlot and I went prone by that low wall near the steel girders. I waited for him to walk by, then whispered "for allah....." and knifed his stupid ass. I laughed for about a minute because he had a heavy MG and we were playing hardcore. Ever since then I always whisper "for allah..." every time I go to knife him now. I usually play as SAS or marines because they have the best camo, and for added effect XD
Later we played with his stupid friend, whom I hate with a sickening passion. I was playing as the Marksman class, the one with the R700 and claymores. I put one claymore halfway up the stairs facing a wall, just to be funny and see who'd trip it, and placed a backup at the top of the stairs just out of the line of sight. Sure enough, after I get enough kills that stupid kid comes running into the building and starts shooting at my claymore with a pistol. He misses, but eventually shoots it and it explodes. As he's running up the stairs, he turns to me, "Haha, Idiot! I got you now, stupid bit--"
That's when he noticed the claymore at the top of the stairs and he stops dead.
-Click-
*BOOM*
I win.
Finally, I remember playing Bog with my little brother and that stupid kid, and me and my little brother had just discovered that bellyflop move (you sprint, then jump, then hold B to go prone midair and make your guy jump just a little bit farther), and so we're running from spot to spot knifing and sniping each other, and all of the sudden I jump into a bunch of reeds and my guy gets bumped. I turn to see my little brother lying there, and we just stare for a second. Then he stabbed me in the face.
