Sure, people have gone on from Penn to become celebrities-- people like...Schatar. And also Candice Bergen. Possibly maybe one of the girls on Ugly Betty, I think. But it's pretty rare to already be semi-famous before even entering Penn. 

Except, of course, if you're Abby Emerson from the Class of '09.

Way back in 2005, this Penn women's fencing champ starred in an episode of MTV's reality show MADE. Quoth the MADE site:

"All 18-year-old Abby wants to do is make her high school's hip-hop step team, something her friends and family see as an impossible task. After all, Abby is the minister's daughter, honor roll student, Olympic hopeful fencer and prospective Harvard student. So when she breaks the news to her friends and family, they are unsure whether or not she will be able to achieve her goal. [...] In this episode of MADE, we watch this 'goody goody' test her limits to show everyone around her that she isn't the quiet, studious smarty pants they all see her as and prove to them that this dancin' diva has a wild side."

Incidentally, that's also basically the plot from Footloose.

Check out the MADE site for pics and a recap (no video, bah) of Abby's trials and tribulations. And also laugh/cheer/whatever at the fact that she's continually referred to as a Harvard hopeful- sorry Abby! Although if your Facebook pics are any indication, The Social Ivy seems to have been the right choice for "the dancin' diva".

Source: Rumors, and the confirmation of said rumors through the Internets.