I suppose strictly speaking, this should go in the tribute band section, but Zappa Plays Zappa is a lot more than that. Fronted by Dweezil Zappa, this band is as good as any incarnation of the Mothers. The show concentrates on the music and doesn't have the comedy elements of a Frank concert, but is brilliant in its own right and a wonderful reminder of how truly great Frank was.
Check out the videos, highly recommended. I just ordered the DVD from Amazon.
Zappa Plays Zappa