White Knight Chronicles was released just shy of a year and a half ago. We found the game to be a pretty good single-player experience and a decent co-op experience. A week from now (June 9th for AUS, June 10th for UK, and June 8th for the rest of PAL), its sequel and prequel will simultaneously be hitting the store shelves on two different consoles.
White Knight Chronicles 2 will be returning to the Playstation 3, this time with 6-player online co-op (up from 4-player online co-op). As a pretty sweet deal, the original White Knight Chronicles will also be included on the Blu-Ray disc. White Knight Chronicles: Origins will be making its series debut on the PSP complete with 4-player online co-op. It takes place 10,000 years before the events of White Knight Chronicles. If you're interested in either (or both) of these games, or just want to see some medieval gundams in action, make sure to check out these launch trailers:
EDIT: Apologies about the confusion with release dates. These games will only be released in June for Europe; North America will see them released later this summer.