While it sounds like a contradiction in terms, the urbane bluegrass music genre is exploding. And one of the most interesting disciples is Adrienne Young, performing with her group, Little Sadie.

What sets them apart (say from Alison Krauss and Union Station) is the subtle aura of social commentary Young brings to bear, both with originals and her apt choice of old-timey tunes that seem to speak to today's issues. Adrienne Young and company pick and sing 'em tonight at World Cafe Live (3025 Walnut St. 7:30, $11, 215-222-1400).