Stuff in My Drawers Day

Rebecca is currently studying the Immune System in her human anatomy class, and last night, I pulled out my 10th grade presentation to learn her a thing or two about them antigens. While searching through my portfolio of oversized art, I came across a batch of drawings from the Cartooning class I took at the Torpedo Factory in 1992 (which was really just an excuse to spend too much money on oversized paper and then waste it).

Here is a cartoon I drew in one of those classes. I'm guessing the sign is blank because I was never clever enough to come up with a good punchline, and not because I was being existential (existentialism starts in about 11th grade). Can you do better? What would you write on the sign?