The three favourite games I have on my profile are all comeback games. I'll post them here as well though.
Big Income 2 vs 2 Medium Earth
http://warlight.net/MultiPlayer?GameID=3430948After an initial income advantage, I was down 435 to 265 income on turn 8, but had a large stack of 257 ready to invade. Still, it took 6 turns of careful maneuvering to catch up in income.
Asia 2 vs 2
http://warlight.net/MultiPlayer?GameID=2988737Another game with a big income disadvantage, about 46 to 70, but managed to come back after weaseling my way into a bunch of my opponent's bonuses.
Tic Tac Toe Reverse Income
http://warlight.net/MultiPlayer?GameID=4740722Very interesting settings, I screwed up the first turn and went down 1 army and got a horrible position. I managed to correctly anticipate my opponents moves though to get the reinforcement card first, and ensure they didn't get theirs, earning me the win.