Since you mentioned Halloween, I thought I would throw in mine from this weekend. I was a police officer.
1. One guy came up and said that he was underage and was I going to arrest him. I said no.
2. Three of the guys dressed as Chipendale dancers asked (at seperate times) if I was going to arrest them for indecent exposure.
Last year, I was dressed as a nurse.
3. One guy grabbed his crotch and said, "I have a headache." Eww.
4. "I need a nurse, I have a broken heart." To which I replied, "Sorry sweetie, I don't fix them I only break them." Equally as cheesy I know, but it got him to go away.