Dave Grohl comes home -- highlights from the D.C. episode of "Sonic Highways"

Dave Grohl likes to flood the zone. Rock-and-roll's friendliest superstar was at the Smithsonian on Thursday night for a screening of "Sonic Highways," his new HBO travelogue-rockumentary series about the making of the forthcoming Foo Fighters album. On Friday night -- as the second episode of "Sonic Highways" aired on screens nationwide -- Grohl was preparing to hop onstage at the Black Cat for a much-smaller-than-usual Foo Fighters gig. And on Sunday night, he'll be gabbing about the entire "S...