Picked it up on Blu-ray. I got it at Borders, where I never usually buy music because it's always full list price, but I had a gift card and a 40% Off coupon, so I'm sure it worked out. Then I forgot to use the gift card, so basically I bought myself a birthday present. Still, it was the best present I got, and yeah, it's a kickass documentary.
The bonus footage is amazing! You get the "long version" of a lot of those little interview snippets scattered throughout the doc, including the "Rush has dinner and slowly gets drunk while the cameras roll" and some great historical footage, including a completely amazing performance of "Working Man" by the original lineup.