Captain Squeegee. A rare combination of ska and psychedelic rock. Their album To the Bardos! is particularly great, and ranks among my top 5 albums of all time.
Black Bonzo. A modern-ish prog band that sounds straight from the 70s.
Bubblemath. Progressive jazz fusion. Their first album was light on the jazz and pretty low-budget, but their second album, Edit Peptide, is the best in the subgenre, IMO.
Lotus Child. Indie alterna-rock. They only had one album, but it's creative and interesting.