2. Scrubs, season 6, "My Musical"
The Premise: A patient (Stephanie D'Abruzzo) finds herself hallucinating, believing that everyone around her at Sacred Heart Hospital is singing instead of speaking. The episode follows her stay at the hospital, where she just happens to witness a whole bunch of important character moments in the lives of our favorite doctors.
Best Song: "Guy Love." Or "Everything Comes Down to Poo." But mostly "Guy Love."
Scrubs was always at its best when it was mixing ridiculous comedy with real emotions, and "My Musical" did that incredibly well. The songs were, in fact, ridiculous (see: "Everything Comes Down to Poo") but they carried the cast to some significant conclusions by the end of the episode, and carried us through some significant feelings.