There are two "expansions" for GTA 4 exclusively for the Xbox 360, the Lost and the Damned (the one where you play as the biker that shows up during the museum mission), and the Ballad of Gay Tony (an expansion which brings back much of what was originally missing from GTA 4, where you play as an assistant to Gay Tony doing the various jobs that need to be done to keep his criminal side undercover). There is also a disk coming out, Liberty City Stories, which contains both of the expansions that doesn’t even need the GTA 4 disk to play them.