G+: A really fun and novel take on rogue-likes

David Coles
A really fun and novel take on rogue-likes. It's like someone took a dungeon crawler, crossed it with DDR and slapped on an awesome chip tune soundtrack by Danny Baranowsky. Highly recommended (and on discount for the next day or so)

Crypt of the NecroDancer

Matt Giuca

David Coles
Also runs on Linux (though crashes because my Microsoft Arc Keyboard presents itself as a Joystick...)

Jeremy Visser
Reminds me of Audiosurf.

David Coles
Same genre of "beat matching" game. It even has a mode where you can use your own music, but I've not had too much luck with it (always instant-ends the level)