S5 E11: Dean and Sam check themselves into a mental hospital so they can investigate a monster that is attacking patients.

Realizing his friend could really use a break, Lee brought Dean on stage to sing the extremely on-brand Dukes of Hazzard theme "Good Ol' Boys" by Waylon Jennings. Yes, this episode not only gave us Happy Sam, but also Karaoke Dean and it's not even Christmas.