Basically you have to say a word which An applies too. The aim of the game is to never repeat a said word or you fail. "An orange" "An apple." Those are just examples, feel free to use those. I'll start. An Hourglass.
An only is proper when the word after it starts with a vowel. In any other case it would be A not an. (Sorry it made me cringe for a second.) xD An elephant