AJ Bombers, a Milwaukee burger joint, recently harnessed the power of Foursquare to assemble a flash mob of 161 hungry patrons, resulting in a 110% increase over the typical Sunday sales. How's that for social media ROI?

Owner Joe Sorge was asked to help raise money so the Milwaukee Social Media Community could host an event at the popular South By Southwest (SXSW) Interactive Festival in Austin, TX. Joe says the idea came when he realized how many of his restaurant's patrons were getting into Foursquare, the location-based app/game that allows users to earn points and special badges for "checking in" at various locations.

One of the harder Foursquare badges to obtain is the Swarm Badge, which requires over 50 other users to be checked in at the same location at the same time. So Joe used Twitter and Facebook to encourage people to come out to his restaurant and check-in via Foursquare in order to obtain the Swarm Badge and help raise money for the Milwaukee Social Media Community at the same time. The idea took off and was quickly disseminated through the social media networks of the restaurant's fans.

Watch the video (below) from the event, or check out Joe's Flickr photoset.

Want to know more? Check out this Q & A with Joe Sorge where he talks about how he pulled it off.

Cross-posted on the bfg blog.