The facts about the classes:
While people think the classes in Harry Potter mean something that they'll use later in life, they're wrong. The classes have completely different meanings.
Herbology: In other words the study of the biological properties of your back yard.
Potions: Ways to brew different drinks: Budweiser, Wine, several other dangerous liquids, and Mountain Dew.
Defense Against the Dark Arts: Preparing you to well, that's obvious, fight giant mutant meatballs that have spaghetti guns.
Care for Magical Creatures: Learn several ways to keep our Goldfish alive for more than 24 hours.
Charms: A class (traditionally taken by nerds) in which hopeless romantics learn to woe the ladies.
Transfiguration: Usually taken by nerds who take charms, teaches the student how to transform into something else while hiding from your rampaging girlfriend who's out to kill you make it look like an accident so she won't have to look at you long enough to say "Its over"
Divination: Learn long division and for a rebellious streak, teach multiplication on the last name (ooo that's bad)
Study of Muggles: Teaches said wizard/witch about useful things they will never use. (Cake class for jocks)
Ancient Runes: Takes students to ruins where they learn a new language and pit their hand-to-hand combat skills with giant talking video cassettes (self-explanatory)
That's it, and if I missed any please tell me.