The O.C.: The Chrismukk-huh (2006)
This is by the far the strangest of the Chrismukkah episodes. It starts out in a mundane enough fashion - Ryan is mourning his deceased ex-girlfriend and is having a crisis that his new relationship with Taylor is getting serious. The two of them have an argument on the roof, fall off, and wake up in an alternate universe where neither of them ever existed. A few caveats to this. First, this isn't my interpretation: Taylor identifies it as such. Also, based on her knowledge of science-fiction, she decides they need to fix the problems of the characters in this bizzaro-verse before they can return home. Of course, everything's mixed up: Seth's parents are divorced, and his father's new wife is having an affair with Summer's fiance, who is played by a young but very recognizable Chris Pratt. They manipulate and influence everyone with mixed results. In the episode's best scene, Seth demands Ryan tell him who he is and what's happening. Finally, Ryan just