Stop me if you've heard this one...
A Brit, and American, an Australian, and a Vietnamese man enter an elevator. Suddenly the air begins to smell foul. The Brit wrinkles his nose and asks 'Who farted?'. The American waves his hand in front of his face and demands 'Who farted?'. The Aussie gags slightly and asks "Who farted?". The Vietnamese guy glares at everyone else and demands 'I did!'.
Explanation: in Vietnamese, the expression 'Who farted?' (ai dit) is pronounced 'I did'.
