It's a 48 hour game jam where a theme is selected and then you have to create a game fitting that theme. If the game created during this event is popular enough the developer or another developer might decide to flesh it out after the event. They happen every 4 months and is a good thing to pay attention to. 

I was hoping to participate in this one but I didn't realize it is the same time as my finals. Ah well. 

It already started. However, you could also do a personal challenge by attempting the theme. There is a global game jam coming up Jan 24-26 http://globalgamejam.org. The game jam is non competitive it's a lot of fun if you can . Last year I helped program with Earth Pulse by programming some of the scripts and designing some of the logic and strategic elements.  The lead designer never played a strategy game before and I had not yet used Unity so the majority of the programming was done by a friend of mine.  http://2013.globalgamejam.org/2013/earth-pulse.