Short summary: Watch Buffy try out for cheerleading. Watch Amy try out for cheerleading. Watch all the contenders for being a cheerleader suffer magical accidents. Watch as Buffy and friends figure out Amy is a witch. Watch as it turns out it's not Amy at all: it's Amy's mother, yearning for her glory days. Watch Giles break Amy's mom's spell. Watch Buffy's awesome fight. Watch as Amy's mom gets trapped in a trophy.
Analysis: the first episode not about vampires. In short, this episode could have broken Buffy, but ended up being the episode that finally showed what Buffy could be about: monsters as metaphors. The previous episodes had metaphors, yes, but they weren't the main monsters, they weren't the main plot. This time, the metaphor and monster are the same: my mother is jealous of me. "Youth is wasted on the young."
Just as the Master and Luke made "The Harvest" about fathers and son, so did Catherine and Amy make this about mothers and daughters (although Buffy and her mom started that a bit in the last episode, it kicked into high gear in this one). This theme will actually come back and forth throughout the series.
Note again: the DVD was glitching on this episode too. If it gets worse, I may have to buy a new DVD set. In particular, the image at the end of the episode of the cheerleading trophy just froze.