http://uncyclopedia.org/wiki/Autocross
"The primary attraction of autocross is that it is a relatively inexpensive way to meet teenage girls brought to the races by their pimply faced, baseball-hat-on-backwards, Honda CRX driving boyfriends. Many clubs use this aspect of the sport to try to attract new members by featuring condom giveaways for novice drivers."
"Classes and rules vary from sanctioning body to sanctioning body, but typically you get stuck into what ever class the event master said you were going to run in. This process allows his buddy in the Z06 to win each weekend against a gaggle of rusty MGB's."
Read the related articles too, the ones on Nascar and F1 are particularly priceless...