I was in a largish guild called Order of Chivalry, although I can't remember for sure which server we were on. Had the privilage to be on hand for the very first (for our server) summoning and subsequent defeating of...I don't know what. Something huge out past the glowing wall, that spawned tons of very high level adds.
Got some screenshots floating around somewhere. I'm pretty sure that later on a good PW could solo the thing, but at that time with very few max players, it was a big deal...hundreds showed up to help take it down. I was a mid-level PS and my buddy was a mid-level TT so we just grouped up and went around jumpstarting and repairing broken down folks. Good times :D