TV tonight: 'Neighbors,' 'Supernatural,' 'South Park'

• ABC's 'The Neighbors' moves to its regular time slot after 'The Middle'
• CW is the lone network not showing the presidential debate, opting instead for the 'Supernatural' premiere
• 'South Park' finally takes on the childhood obesity epidemic

The Neighbors
ABC, 8:30 ET/PT

ABC's my-neighbor-the-alien sitcom moves into its regular, post-Middle time slot with an episode in which the humans persuade the aliens to put their kids in a regular school and then take them for their first-ever trip outside of the neighborhood — to a local shopping center. So that's their first reaction to discovering they're surrounded by space aliens, they take them shopping? Obviously, The Neighbors is a fantasy, which gives the writers a lot of leeway in how the aliens behave. But it's awfully hard to get a fantasy to work if we don't believe the way the humans behave and react, and really, who would act like that?

Supernatural
CW, 9 ET/PT

ABC, CBS, NBC, Fox and PBS are all offering live coverage of The Presidential Debate (9 ET/PT) — but not CW, the only broadcast network to stick with entertainment. Which means fans of Supernatural, which kicks off its season tonight, get to see Dean emerge from Purgatory and reunite with Sam. Unfortunately, Sam isn't quite as thrilled by the reunion as Dean might have expected.

South Park
Comedy Central, 10 ET/PT

Surely you knew this was going to happen. It was only a matter of time before all those stories about the growing scourge of childhood obesity filtered down to South Park, where Cartman is finally ready to admit he's fat — so he can get a mobility scooter. And no, that is not what the weight-loss advocates had in mind.