Just go as a student of sexology and wear a terry cloth bathrobe.

Or go as a student of women's health and make a sign that says "free breast exams."

I went to art school, so if you really want to be an art student, you just wear t-shirt and jeans covered in paint smudges. Not as exciting as it sounds. We only get dressed up when we need to sell something. These days I occasionally do some work with rich artists (don't know any snobby ones), they wear ratty clothes when they paint too.