Motorstorm 3D Rift is an updated version of Pacific Rift with stereoscopic 3D support. It includes 10 tracks, 10 race events, multiple playable vehicles, and yes, it’s playable in both 2D and 3D. It costs $9.99 on PlayStation Network. It looks like Sony released this to keep Motorstorm fans busy while Evolution Studios toil away at Motorstorm: Apocalypse for a 2011 release.
You can watch a trailer for 3D Rift at the PlayStation blog, linked to above.