"The Empire Strikes Back," the best Star Wars movie not named "Star Wars," was released on May 21, 1980. Exactly thirty years later, the Dodgers will commemorate this event by giving away Boba Fett-themed THIS IS MY TOWN T-shirts as part of their "Empire Strikes Back Night & Poster Giveaway" on May 21 (2010). Tickets cost $45 and can be purchased here.
Now we just need the billboard version.
(Thanks to Josh "No Disintegrations" S. for pointing this out.)