Depends on how exclusively up to date you want to be.   But PDQ Bach for instance (no spring chicken, that's for sure) is still very much active--I get lists of his appearances since I'm on his e-mail list.

Dry Branch Fire Squad is still around (I hope, at any rate), and Ron Thomason, the leader has a great-- appropriately enough, dry--sense of humor (e.g. "We believe in aggressive ignorance in bluegrass music").