Well since we're dealing in old, lame jokes....
Two men are working out at the gym, and when they're done they go to the locker room and change. One of the men puts on a pair of pink panties. The other one says, "Ummm, Fred, I don't mean to pry, but how long have you been wearing women's underwear?" Fred replied, "Ever since my wife found a pair in the glove compartment of my car."