This is a band called Mission South, with whose lead singer I was in the same fraternity in college. Their website is here. They call themselves "Soul Rock", and listening to them I'd say you can pick up blues, jazz, rock and alternative, all with a classy modern sound. They are currently in a contest for the Best New Band in DC, and you can vote for them too unless you happen to know of other new bands from our capital and happen to think they are better... I guess that's how surveys and contests work, huh?