I had this one incredible battle one time when I seen a dragon fighting two mammoths and two giants so me and my companion ran over to join in the fun and while everyone was fighting each other along came a sabre tooth tiger to add to the melee. I had also summoned a flame atronach to help me out. And after all 8 of us had finished scrapping I'm happy to say it was only me and my companion that survived to tell the tale. So anyone else had a mass battle yet in skyrim.

I just made a post about it but I'll put a short version. I'm in a dungeon right now, 6 Draugr Deathlords, 1 Restless Draugr and 1 Draugr Scourge. I play on Master and only use loot I find. Nasty.