Okay, so aliens have arrived in your backyard/apartment/cardboard box and have chosen you to teach them what these "veedeooh gaemzzz" are but they want to make this quick cause they need to kidnap cows, anal probe some hillbillies, drop playing cards and kidnap Harry Mason. So you must give them one example of an awesome game from every gaming system you've played. You can only choose one, or they will probe your ass and start seeing what happens when they splice you together with cows so one gaming system (PC counts as one system) and only one game as your choice of the best game for it.