There are a lot of them.
Hayseed Dixie are fairly impressive if you like Bluegrass.
( Wicca'd Witch needs ideas for a new sig on..., Mon 6 Jul 2009, 19:22, archived)

They're great fun, especially when they break into Duelling Banjos.

( Harold Bishop's Love Child some sort of terrifying sex magician., Mon 6 Jul 2009, 19:23, archived)

Oh yes.
Apocalyptica are quite impressive too.
( my other username is a porsche , posting shit pictures so you don't have to, Mon 6 Jul 2009, 19:25, archived)