The Common Application gives students a lot of freedom with personal essay option #6: Topic of Your Choice. Be careful not to abuse the freedom. Having unlimited choice doesn't mean that all topics are appropriate, nor does it mean that you can submit something that really isn't an essay. Keep the comedy routine, the poem and the abstract art for another purpose. Whatever your topic, your essay needs to reveal your personality, your character and the reasons why you'd make a good campus citizen. Before diving in on this topic, be sure to check out these 4 tips.
The essay is an important part of your college application if you are applying to schools with holistic admissions. For tips and sample essays for each of the Common Application essay options, see this article on essays.