In WoW, leading a 40-man guild raid on Orgrimmar to kill Thrall and Vol'jin. A server first, and as far as I know it hasn't happened since. Owned them both, then fought Horde back for about ten minutes before finally falling to them.
A pic after killing their leaders, fighting Horde in the streets:
WoWScrnShot_020308_011452.jpg - Image - Photobucket - Video and Image Hosting