I go to midnight releases for every game that I get a chance to go to, except Call of Duty midnight releases.
Earliest one I can remember going to was the Twilight Princess one at my gamestop, nothing special really happened at the release itself.
The Super Smash Brothers Brawl one is no doubt the best one I've been to yet, there was a Melee tournament, and I got 1st place winning both a free copy of SSBB and a poster.
I've been to about 15-20 of them since then, most recent one being Halo 4 I believe.
I love midnight releases, always meet at least one cool person at them and get some fresh air. I'm usually up all night anyway, so no loss for me.