Vipassana retreat?

I heard some very good things about the North Fork Vipassana retreat center last weekend.  (At least according to the guy I talked to, this particular one is excellent and not cultish.)  I'm hesitant to commit a full 10 days to something like this without really knowing what I'm getting into.

If any of you have done this sort of thing, I'd love to chat with you more about what to expect.