Episode #4.10 (mid-season finale) airs tonight, November 20, 2008, at 9 pm/ET.
Supernatural will return with new episodes on January 15, 2009.
Reminder: Episode #4.10 will be pre-empted in Pittsburgh, Pennsylvania (WPCW) for the Pittsburgh Steelers game, according to Rob Owen from the Pittsburgh Post-Gazette. The episode will relocate to November 22 at 8PM (check kdka.com for confirmation).