6. 'Once More With Feeling' (Season 6, Episode 7)
Yes, other shows have done musical episodes. But few sell them as anything more than a stunt to perk up a show that's sagging in its later years or to show off a cast's Broadway-ready talents. That's not how Buffy rolls. First, Whedon wraps the musical in a “realistic" – at least for the show – premise: A demon has cast a spell over Sunnydale that causes everyone to break out into song and dance, often revealing hidden feelings in the process. While the gang tries to figure out how to disrupt the spell and fight the demon, they, too, drag their secrets into the light. And in a brilliant climactic fight-scene/song-and-dance number, Buffy finally admits that she resents her friends bringing her back from her Season 5-ending death. It's an epically weird, haunting song and a tremendous showstopping performance by Gellar. Once more, Buffy turns something conceptual into a way of getting inside these characters' heads. And that's not even counting the "Bunnies" tune.