Two times I've seen a play called 'Fully Committed.' (We liked it so much we took friends to see it the second time.)

This play has only one character, and out-of-work actor who answers the phone in the basement of a trendy restaurant. He plays himself and he plays every person calling him on the phone. I forget the actor's name, but he was incredible.

He could be a man, a woman, a Japanese tourist, the boss, the British hostess upstairs ("I'm sorry, darling, but the staff meals have all been eaten."), a supermodel's gay personal assistant, his own dad, anybody. It was amazing to see the new ways he spoke, moved, and held himself as he became the new person. That is the essence of acting.

Imagination is basic to entertainment, and it's perfectly possible to imagine that a person is a member of the opposite sex. Heck, I could imagine I was an octopus, if I tried hard enough.