Also, the isolation is spot on. It can be pretty depressing to be trying to, say, do SICP on internet advice, while people around you ask why you don't just take a Java/C++ class. I applied in large part to meet others truly interested in programming, and though I can't make it this time around, HS is tops on my list of things to do in 2012.
A quick correction: Hacker School application page is actually http://www.hackerschool.com/apply. If you just want to talk or are looking for a job, Zack's link is the way to go.
There are some similar concepts, but without the programming part. Kaos Pilot, Knowmads, etc...
We filter on intellectual curiosity and love of programming, so people don't typically have trouble finding interesting things to work on, especially since they're surrounded by other curious people working on interesting and hard problems.
I believe the youngest student was 19 and the oldest somewhere around 40. For the upcoming batch, most students are in their 20s or 30s (I don't know for sure, because we don't ask).
