This is one of the better movies that aired in one of Disney Channel's better days. Basically, it's about two teenage sisters switching places, one of which is a popular and gorgeous yet airheaded senior that works hard to become the high school's Winter Fest queen, while the other is a socially inept yet bright and undeniably cute sophomore whose major goal this school year is to succeed in the school's science fair. The contrast between each of the girls makes for a very interesting and fun movie to watch.
It's very much aimed towards younger audiences, although Disney obviously disagrees with quite a few of its themes and somewhat suggestive scenes. It still retains its status as a PG-rated movie. The plot is easy to follow, and the characters are even easier to fall in love with.
If you liked watching this movie all the time on television, I suggest you grab the DVD. The commentary alone is worth the investment.