Xbox 360 game in the mid-priced range, help?

I'm looking to get a fun game to play with my sister. I'm on COD:WAW and GTA4 now so I don't need any kind of game like that. I was looking at a racing / party / maybe co-op action adventure game? I bought Amped 3 but didn't like it so much so now I'm looking for another. I was looking into Viva Pinata (or Party Animals), Rayman Ravids or w.e, and multiple different racing games. Any games someone can recommend that would fill this void?