Customers visiting participating L.A. Subways can play a series of challenges on their mobile phones for a chance to win tickets to the L.A. premiere of "Green Lantern," movie tickets or exclusive access to Green Lantern wallpapers and videos.
To play, users download the special Subway SCVNGR app on any iPhone or Android device. Sample challenge: Take a photo next to a Subway logo while flexing your superhero muscles.