I don't ;o) I just say : "Oh, it's an offbeat computer game. I can choose different characters and move them around with the mouse, and once in a while I click a button to take a picture of the action." At those rare occasions when you come across an "artiste" who feels threatened by this instant art-machine, just add "Just a hobby, really." That'll save you hours of listening to the "It's not art" sermon. Most people stop listening after the words "computer game", anyway ;o)