SubwayFacebook.jpgFive…five-dollar…five-dollar foot long!

Subway waited until Christmas Eve to jump on the Facebook bandwagon, launching a fan page with a 20-second commercial-sneak-peek video featuring Olympic Games swimmer Michael Phelps and a sweepstakes in which the sandwich chain will give away 10 $50 Subway cards each week through Jan. 24, Inside Facebook reported.

The page has already tallied more than 222,000 fans and, as per Facebook’s new promotion rules, members of the social-networking site do not have to become fans to enter the sweepstakes.