As techgirl mentions, most BBQ places close at 9 PM. It does look like both Sonny Bryans and Spring Creek BBQ are open 'til 10 on Fridays. Both are chains with decent but not memorable chow.

A good source of restaurant info is www.guidelive.com - from there you can pick your neighborhood, restaurant type and so on, with full details and operating hours. They also give their recommendations on best bets (the "Guide Pick" places are their favorites.)