One year I went to a party straight from work where I had to wear a suit and tie and didn't have time to go home and change. When I was asked where my costume was, I hefted my brief case and said "I'm the scariest thing you've ever seen. I'm an IRS tax auditor. Show me your books." It got a few laughs. It was either that or pt on a pair of really dark sunglasses and tell everyone I was a Secret Service Agent.