In 2007, we counted down to the third season of Supernatural by rewatching the entire series, one episode per day. The schedule is here.
Only moderators have posting access. Watchers are invited to post their thoughts, recs, squees, analyses, or kitty pidgin in the comments to each episode's discussion post. Expect spoilers for all aired episodes, but please refrain from posting spoilers for next season. Be excellent to each other.
If you can't keep up with every single episode, just jump in wherever we are!
For the countdown to season four in 2008, SPN_Replay recommends spn_rewatch for all your SPN rewatching needs.