Jumping in, there's a lot of information at remixers_lounge and you can see last year's stuff at remixredux09. Now, that's the main Remix Redux which is multifandom, but there's also spn_remix, which is SPN-specific, kamikazeremix which is multifandom and intense in that you chose the story of yours that will be remixed, meaning you're assigned a specific story TO remix. There are a lot of other remixes in other fandoms, too, I think. I've done a bunch of them, and it's generally a lot of fun. Just turned in my story for remixredux today!