You know the two man cannons in the middle of Avalanche where the Sp'laser spawns? Some stupid noob took a ghost up there, but he couldn't go all the way. He just got pushed back and forth between the two cannons. I thought he made it across, so I decided to go next. Then he was pushed off the other man cannon and splattered into me. I would have booted him if the game had let me. Needless to say, we lost the game.
This isn't a betrayal, but it was weird/funny. I was driving a Warthog (stupidly, I might add) into the middle of a fight in a CTF game on Standoff. I landed inverted next to a guy with a shotgun. He hit me, but I wasn't affected much. Then, some guys threw some 'nades at my ride as I crawled out. The Warthog flipped and launched me to the other side of the map, almost off the edge. Luckily, everyone was involved with the skirmish, so I grabbed the other team's flag. Crazy stuff.
Also, another strange occurance. Awesome, but strange. It was under Camp Froman (as it was called in H2). I had a bubble shield, and an Assault Rifle as I ran from under the Brute Shot/Grav Lift spawn. A member from the other team was chasing after me, so I thought I would deploy my Bubble Shield and wait for him to be heroic and rush in. Meanwhile, he was thinking he would try to stick me with a Spike Grenade. We threw our equipment at the same time. His 'nade bounced off of my bubble and into his own face, giving me the kill. Thus, it became the "Bubble Kill." Both of these non-betrayal stories are true and in my fileshare... I think. If not, I'll be sure to change that.