I'm not a big R&C fan, but this looks like it could be a lot of fun:
http://blog.us.playstation.com/2010/08/17/ratchetandclankall4one/
[quote name='USPSBlog']
We’re excited to announce that we’re hard at work on the first ever one-to-four player cooperative, online/offline, drop-in/drop-out Ratchet & Clank title, Ratchet and Clank: All 4 One!
We knew from our earliest meetings that we wanted to give players a chance to play in the Ratchet Universe with Ratchet and Clank at the same time. And after we started, we felt an almost moral obligation to include Captain Qwark and Dr. Nefarious; there was just too much comedy potential in bringing this group together for us to pass up the opportunity. Their bumbling idiocy, prickly antagonism, and unfettered evil was a perfect reflection of how we play All 4 One here in the office. I’m looking forward to telling the story of how the four of them find themselves together.
The game is about cooperative play through and through. We want to make it easy to get together with friends and family, get in a game and have fun in the Ratchet universe. We’re working hard to capture the feeling of fighting through amazing battles with other players, whether they are on the couch next to you or playing online half-a-world away.[/quote]
Supposedly will feature full drop in/drop out multiplayer co-op functionality.
http://blog.us.playstation.com/2010/08/17/ratchetandclankall4one/
[quote name='USPSBlog']
We’re excited to announce that we’re hard at work on the first ever one-to-four player cooperative, online/offline, drop-in/drop-out Ratchet & Clank title, Ratchet and Clank: All 4 One!
We knew from our earliest meetings that we wanted to give players a chance to play in the Ratchet Universe with Ratchet and Clank at the same time. And after we started, we felt an almost moral obligation to include Captain Qwark and Dr. Nefarious; there was just too much comedy potential in bringing this group together for us to pass up the opportunity. Their bumbling idiocy, prickly antagonism, and unfettered evil was a perfect reflection of how we play All 4 One here in the office. I’m looking forward to telling the story of how the four of them find themselves together.
The game is about cooperative play through and through. We want to make it easy to get together with friends and family, get in a game and have fun in the Ratchet universe. We’re working hard to capture the feeling of fighting through amazing battles with other players, whether they are on the couch next to you or playing online half-a-world away.[/quote]


Supposedly will feature full drop in/drop out multiplayer co-op functionality.