Recently I've also been getting into more casual/indie genre games. More specifically, games like Beat Hazard and Geometry Wars. What attracts me is the simplicity of the controls, the replayability and the graphics. In my opinion the graphics on these games are amazing. Mainly all the colours going everywhere. And with Beat Hazard, having your own music pretty much control it is epic.
If you don't know what games I'm talking about, take a look at some of these videos:
Geometry Wars: Retro Evolved: