11. BUFFY THE VAMPIRE SLAYER
''Halloween'' (1997)

Sure, the costume shopkeeper seems creepy now. But when Buffy (Sarah Michelle Geller), Willow (Alyson Hannigan), and Xander (Nicholas Brendon) got their Halloween togs, no one had any idea that he was plotting a spell to fuse everyone's identities with their costume. Thus, Buffy becomes a 19th century lass, Willow disappears into her ghost sheet, and Xander morphs into a general, which — clever show! — serves him well later in the series when the united slayers need a field commander. It's so much fun, we don't even need all the gooey love stuff between Buffy and Angel (David Boreanaz) at the end...but we'll take it.