All examples of amusing calls I have overheard. Number one is an oldie, but a goodie.
Tower: "ABC, say again call sign only."
ABC: "Call sign only."
Aircraft in training area to another: "What is your position?"
The other aircraft: "You are in my three o'clock."
International student switching to Tower frequency at holding point: "Tower, ABC cleared for takeoff."
Tower: "Oh alright then. Cleared for takeoff."