In one online game of Battlefield 1942, this troper saw a plane swoop low over an enemy, drop a bomb... then get destroyed by the force of the explosion.
This troper was watching his father play the same game. He got into a fighter plane, informing me that he isn't the best pilot. The plane proceeds to explode from an offshore attack as soon as he begins to move. I sat there for a second before laughing myself silly.
Every time a demoman charges at me and I take him down with a headshot. The backslip they make makes it even sweeter.
During a TF2 session a sentry started to anooy me and I typed to my teammates to "TAKE OUT THE FRIGGGIN DENTRY". My team starts laughing and during the next round they have a conversation a bout what dentries are. I eventually lampshade it by saying "releporters going up".
Whenever automatic and player-prompted voice responses are mixed up. "Engineer is credit to POW! HAHA!"
Using taunts and voice commands together can get even funnier. "Yo is someone keepin' track of my MEDIC! ...BONK!"
At one point, I was eating a sandvich, and right after eating it, I intentionally activated the 'positive' voice command, so right after eating, the heavy said "SOOOOO MUCH BLOOOOOOOOOD!" Of course, I also do 'Negative' voice commands right after eating the sandvich too.
Freezecam shots often provide hilarious screenshots due to the slight delay. Results can vary from closeups to hilarious facial expressions (especially on a heavy) to a sniper waving at you while a scout is standing behind him performing the killtaunt. Corpses can also end up in hilarious poses (especially with the huntsman) and open eyes.
Speaking of the huntsman: Players with arrows stuck in their heads (possible for overhealed heavies and scouts during Bonk invulnerability).
Melee sudden death. Often ends with one player alive on one side capping the remaining points while the survivors on the other team try in vain to catch up to him.
Tricking a sentry into killing the engineer who built it (doubles as a CMOA for whoever pulled it off, usually a spy).
This troper once played a campaign with a friend in Left 4 Dead. During Blood Harvest, I ended up predicting a Hunter's pounce, and moving out of the way. I continued to do this for thirty seconds before a common infected broke the streak and got me pounced. Everyone laughed. Too bad I had H.L.D.J. on aswell, or I would've shouted "OLE".
This troper recently played the sequel with a few friends. One of them, who normally loves to shoot alarmed cars just to be a dick, decided from the start he wasn't going to do that. Naturally, when we got to the fuckton of alarmed cars halfway through the third map of The Parish, we ended up setting off pretty much every alarm on accident.
One friend: S-sorry. Me: It's al-[another alarm goes off]FUCK!
This Troper was playing Enemy Territory Quake Wars and was on the Strogg team. The Announcer said to defend the broken generator that was connected to a door from the GDF.
Me: "The objective says to defend the Generator but we're keeping it damaged."
Other Strogg Player: "It's tough love."
This troper once watched his friend playing Battlefield 2. He spawned as a USMC Spec Ops on a carrier, then immediately took over a CIWS and blew up a friendly helicopter taking off. Then he flew to an enemy airfield where he had a duel with a pro player almost entirely consisting of ridiculously rolling sideways to avoid each other's gunfire. Surprisingly enough, he won despite having only played LAN matches until that point, though a friendly engineer near the airfield was "accidentally" killed by one of his grenades. Then he ran to the nearest USMC base, planted all of his C4's on a friendly Abrams and blew it up. He got perma-banned, but hey, that was fun.
Bad Company 2 has given this troper many good laughs, one of the best being in a defibrillator fight with a friend on his own team. We were on Laguna Presa in squad deathmatch. After he realized that he could get loads of points by killing/reviving me with the shock paddles we ending up having a big battle COMPLETELY IN THE OPEN with the paddles. What made this amazing was that the fight took at least 45 seconds, and that the entire time we fought a sniper less than fifty feet away was trying to kill us. He never landed a single shot.
World of Warcraft - This troper and his friend play a game to see who can start the biggest flame war in Trol...er "Trade" chat (also ICC - general and Kara in TBC).