If you like rhythm games, get DJ Max. The games are pure quality. I think the only one available for the Vita right now is DJ Max Portable 3. I've played that one and it adds some interesting twists to the gameplay.
Edit: Since I've only played them on the PSP, I'm not sure if the Vita will feel well-suited for the game. Because the buttons on PSP are more mushy, they are easier to press and feel good for rhythm games. The d-pad works really well for this game also, oddly enough, since the Vita d-pad feels miles superior. It might not actually make a difference. Maybe I just need to get used to it and it'll be fine for me.
Here's a quick trailer in case you've never heard or seen the game:
Those pink bars on the left and right are new additions to the gameplay. It can also get very challenging. Totally worth however much they are charging you, unless you are not into this sort of thing. :P
