I've had three good ones so far:
1. I was playing assault on the Ghostship map. I took the flag at the beginning, hopped out the window, ran through the vents, threw a TD through the window of their base, ran up the elevator, and got gunned down. I then repeated that about two or so more times. I realized I had time for one more, so I grabbed the flag, rushed through the vents, threw a TD through the window, hit the button to call the elevator down, ran around and went through the door. When I entered, I found two of them looking down the elevator waiting for me and one of them looking out the window. I managed to score unharassed with 7 seconds to spare.
2. I was on a CTF server, with few people. My team was winning 2 to 1, when I realized the other team had left. So I switched to Clone, and no sooner did someone else join the game and go on Trandos. I managed to get their flag, but they got mine first. So I had to go hunt down the guy with my flag, kill him with melee (i was out of nades). This took me all the way back to their base. I then had to make my way back to my base without them getting their first. After I managed to do it, one of their guys left, and I scored three more in a row to win.
3. I beat Kurgan in a deathmatch! ...once.