Quick note that season 6 of Mad Men is now available on Netflix. Good news if you plan on rewatching the final few episodes as catch up.
Netflix and Mad Men are usually pretty strategic as to when they release seasons to the cult fans. Close enough to the premiere date to make them relevant and buzzed about, and close enough that those serious about catching up to to watch the show real-time, probably already purchased it on iTunes.
Either way, I know what I'm doing tonight.