Lots of new stuff this week: Medium, Reaper, Smallville, Supernatural, Moonlight, Doctor Who, and Battlestar Galactica all have new episodes. Check out the listings for episode names, summaries, and times.

I've already talked about the new slate of Supernatural episodes, which are rapidly bringing us down to the end of Dean's one-year contract: this week's episode features John (Jeffrey Dean Morgan), apparently calling from beyond the grave. Smallville promises to be very intriguing: Clark thinks the world might be better off if he had never arrived in Smallville, so Jor-El shows him what life would be like if that were the case. James Marsters and John Schneider both guest star in an episode directed by Tom Welling himself. On Reaper, Sam is forced to try to tell Andi his secret. Yeah, that's going to go well.

And some welcome reruns: Season 4 of Stargate Atlantis starts running in three-episode blocs on Tuesdays from 7 to 10 p.m., starting with the season premiere, "Adrift," which finds the city of Atlantis helplessly floating in space after having to flee the Replicators.