Looks like you can get Avengers tickets in two locations in LA already, even though it doesn't hit until May. The El Capitan, with some pair of special edition 3D glasses and possibly some cool props from the movie to check out,
The other is AMC Burbank 16 with the Ultimate Marvel Marathon. Six movies, that will make you catch up on anything you missed with The Avengers playing last. Just a reminder this is post production 3D for The Avengers, which doesn't go well.
I can't wait for the local news to get people's reaction of sitting through them all, because they have nothing else to report on.