Just to name one, but one that stood out a lot. Halo 3, the name escapes me but it was a downloadable snowy map and my Sangheili clan set up a defensive perimeter, awaiting a clan that was going to raid us. Anyway, we surprise attacked them, they had no idea. We made a great base inside and out of one of the defensive layouts and we also gave them weapons and vehicles. It was an even raid and everyone was happy. A full on 8 v 8 clan raid.
Anyway, we spent a good three hours raiding, they managed to overrun us with Scorpions and Hornets. However, we took back the base as we slaughtered them in long range; close range; air and ground battles. It was such a fantastic, entertaining and authentic battle. Everyone had great sportsmanship and no-one complained about the game, as it was fair and one of the most memorable battles ever.
Long live the days of Halo 3, the good 'ol days.