The joint is packed. The crowd has waited long enough and is becoming restless, anticipating the wild energy that will be forthcoming from onstage. The performer walks out, a burly African-American with dreadlocks, and begins to play the piano—Beethoven. Because this ain’t no seedy bar, it’s the Kennedy Center. Still, Awadagin Pratt wouldn’t be caught dead in a tux. Though his dress and manner have him mistaken for a rock musician time and time again, Pratt is perhaps the most influential and innately talented young American concert pianist around. Having gained serious attention by winning first prize at the prestigious Naumberg Competition in 1992 at the age of 26, Pratt has continued to cause mayhem with his unorthodox interpretations of piano literature. Tonight’s program includes Mussorgsky’s Pictures at an Exhibition and shorter pieces by Bach and Brahms. At 8:30 p.m. at the Kennedy Center Concert Hall. $12-37.50. (202) 467-4600. (Amy Domingues)