Celebs With No Class

This is the time of year when many college-bound guys and girls enjoy their last summer of freedom before heading off to the halls of higher education. While a BA is by no means a Hollywood prerequisite, lately there seem to be a large number of college-aged stars who are choosing nightclubs over bookclubs.

From Lindsay Lohan to Kristin Cavallari, check out which stars are studying hard and which are partying hard.

Lindsay Lohan

Lindsay may not be taking any academic classes, but the just turned 20-year-old is no stranger to pulling an all-nighter. From LA to NY and back, keeping up with Lindsay's nightlife escapades can be harder than getting into an Ivy league school. While teen movies like "Freaky Friday" and "Mean Girls" put her on the Hollywood map, Lindsay seems to have graduated to more adult fair with "A Prairie Home Companion" and upcoming roles in "Chapter 27" and "Bobby."

Hilary and Haylie Duff

Hilary, 18, and her older sister Haylie, 21, seem to do everything together. They've recorded songs together, will co-star in the upcoming film "Material Girls" and enrolled in online courses at Harvard together. With past credits like "Raise Your Voice" and "The Perfect Man," here's hoping their new studies will lead to more intelligent roles.

Kristin Cavallari

Famous for being a real-life mean girl on MTV's "Laguna Beach", Kristin graduated from high school and set her sights on Hollywood. After hosting the short-lived UPN reality series "Get the Party Started," the 19-year-old's quest for fame led to a role in the upcoming horror movie "Fingerprints" and a gig modeling for Bongo jeans. While Kristin may not be enrolled in school, from the looks of her late night antics the underage starlet could teach everyone a thing or two about getting in to the hottest LA clubs.

Mischa Barton

Mischa Barton's character on "The OC" was killed off before she could attend college. In real life Barton's reason for not getting an edumacation is a little less brutal - she just wants to make movies. While the British born actress has aspirations of attending Yale Drama School, with two films in the can and two more set to start production soon, it doesn't look like Barton will be cramming for mid-terms anytime soon.

The Olsen Twins

Mary Kate and Ashley aren't just your typical everyday, run of the mill, beautiful, fraternal twin billionaire babes - the Olsen twins also have brains. The former child stars put their Hollywood careers on hold and enrolled at NYU in 2004. Although Mary-Kate dropped out in 2005, Ashley is continuing on with her education. Regardless, as founders of their Dualstar Entertainment Group, it doesn't look like either of them will ever have to worry about having a job.

Keira Knightley