I'm think 5 teams, each with a different theme/genre (or a different genre/common theme?). You can contribute anything you want to whichever project, but you can only work on one of the five. At the end, everybody votes on one of the projects (if you're competing you can vote, but only for one you aren't working on), and the most popular project wins.

It's kind of an anti-Indie challenge, a challenge to focus the most on what you do best, a challenge to trust others to do the same, and a challenge to comment/communicate enough to function as part of a team. Each project gets a subforum, and you must join that project's "group" to participate in the subforum (via a "Sign me up for..." sticky for each of the projects). At the end of the compo, the subforums are unlocked for all to see; like a post-game "making of."

Finally, each project makes a thread on the main forum where any contributors can do their own post-mortems, or revisions to it. Maybe a 2-week time frame for setting up the first/main teams and establishing the projects, and a 2-week time frame to make the project? (Bearing in mind, nobody has to build alone from the ground up, here.) You could possibly cut each phase down to one week apiece, even.

THIS
PLEASE MAKE COMPO LIKE THIS!! 

Match-3 game for a compo, but maybe I'll continue work on this after compo.
Frame, background, coins and exp will be changed.

@Kicks: I like the one with mark more, and this with hue messing looks better.

@kevglass: lovely character  

Finally forced SFML to work.
It isn't working under newest (v. > 10.10) ATI drivers 

I see what you did there  
 

I'll try to write something tomorrow, I'm sleeping too little lately 

Piece of nice drawing, but it's strange that my philosophy is nor like Retro nor Ali. I liked the timelapse but Ali's video was more like I can learn something new about game design.

My advice: don't make compo about multiplayer games (even not via internet mainly), so it won't be so hard to check them.

This game is awesome, I like to play it with my friend on boring programming lessons.

[XRA]

@XRA: This is sick 

*Sigh* Looks like I'll have to scrap my project...

Why u?
It's fish's fault 

                                                                                                                                                                                                                                                                                                                                                   

Phenomenon-Thousand Foot Krutch
It's old, but still cool.

It looks nice but I'd like to see some in-game screen shots
  (funny smiley)

@Manuel: +1

@Topic: I like them

You can't! 

[ANtY]

Heroes of Newerth:
ANtY

Steam:
ANtY

League of Legends:
ANtY93

I don't believe in any gods, only in my Theory of Infinity, I could write a book about it if I wouldn't make games. 

I like him more without mouth, also he's easier to animate with shorter legs, sorry.

@Veo: It's look cool