You might know him as, “the handsome grandson,” “the outta work superhero,” or by the name on his birth certificate, “Dathan Harbor.” But chances are you’ve never heard of Flex Mathews by any of his many monikers. You may have no idea that, since he moved to D.C. in 2002, a rising star has been right under your nose. The rest of the country seems to be noticing. In 2005, URB magazine named Flex one…

MONDAY: >>Lucinda Williams brings her raspy voice to the D.C. tonight. Her Tom Petty-inspired brand of roots rock can be heard on her latest album, Live At The Fillmore. Or you can catch the real thing tonight at the 9:30 Club. $35, 7:30. >>Grab your Coke, gel your hair, and spend the evening with the man who made teenagers and soccer moms wear out their voting fingers in 2003. Clay Aiken at Wolf Trap, $25…