There's a huge range of prototypes to choose from this year, so go take a look at the pitch videos and make your choice. If you buy the bundle at $5, you'll get prototypes from previous Amnesia Fortnights, and if you buy it at $15, you'll get previous Amnesia fortnight prototypes that have been made into full games!
The community developed Amnesia Fortnight also returns this year. This year, you can choose between three pitches, and then you can join in on the development or just watch it as it happens. You can see the video below (you might notice a familiar name on the pitch for the third prototype :P). Feel free to vote for whichever one you like most over at the Double Fine forum.