Ok, this looks fun. Coming this fall, from the same people behind Rock Band - a company called Harmonix - a new game called Dropmix. It lets you play DJ by mixing up parts of different songs to create your own original mashups/mixes. Actually it looks like it will require less skill than Rock Band or Guitar Hero, but just as fun.
The general idea is that there will be playing cards that you drop into 1 of 5 different sots on the console, and the cards will play different parts of different songs - making unique mixes of your favorite songs.
The initial song list includes music from:
Weezer, Franz Ferdinand, Fall Out Boy, Chvrches, Cake Sia, Skrillex, A Tribe Called Quest and a bunch more.
The game comes with "an electronic DropMix Board and 60 DropMix Cards," but more cards will be available in Playlist Packs (16 for $14.99) and Discover Packs (5 for $4.99).
Alternative Press breaks it down in full.