The finale was a big invasion by the Rikti, the alien bad guys whose initial invasion created the current state of the CoH world (that is, super-bad guys all over).
It was pretty cool. There were some hiccups -- a bug prevented some of the Rikti from fighting, and there were more players (I think 60,000) than the devs could handle -- but it was fun to stand with the other heroes of the city and wait for the aliens to come.
There were some very cool suggestions on some of the fora for improvements next time. One in particular that I agreed with was a change in the location of the event. The way it went was that the aliens spawned from portals around the center points of each of the zones where they invaded. This is pretty sensible. However, the suggest I rather liked was that the aliens start in some entrance point -- like coming out of the train terminals or through the gates between sections of the city or from portals located at the peripherals -- and make for the center point. That would have been fun, trying to defend areas of the city against invaders moving over the ground instead of jumping on the spawns as they came out.
I'm excited about playing for real. I'll have to see if I can find a group to hook up with. My two best superhero buddies are not playing, so I don't have built-in pals. At least, they're not playing yet. :)