Add the SoCo Music Experience to the expanding list of free summertime events in the Madison area. This year, the Southern Comfort-sponsored fest takes place on Sept. 6 at the Alliant Exhibition Center's Willow Island. No bands have been tapped for the 21-and-over affair, but Southern Comfort has announced that Queens of the Stone Age, Gnarls Barkley and the Black Keys will each headline one of its other events. Last year, ageless psychedelic oddballs the Flaming Lips headlined the Madison stop and drew thousands to the late summer freebie, which also featured Cold War Kids and Cowboy Mouth. The distribution of free drinks spiked with the sponsor's sweet, fruit- and spice-flavored whiskey didn't hurt the gate either.