It's my boss' birthday this weekend so I made him a t-shirt. He's a doctor who ALWAYS wears bowties; he's known at the agency for it. He has bow ties in every colour and design; he even has one with the H1N1 virus floating around inside it lol (he is the Director General for the Center of Immunization and Respiratory Infectious Diseases).
Anyhoo... hopefully that bit of background will help you understand the joke :P
He took off his real bow tie and wore this to his high level meetings today - gotta love him!