This is probably a weirdly worded topic, but are there any games that have a certain area, task, or minigame that someone you know likes to play?
For example, my ex loved to play the gambling section of any game I was playing. Like the casino portion of Dead or Alive: Xtreme Beach Volleyball and the betting sections in Kitten Kaboodle (and old Konami arcade game I used to play in MAME).
Also, she'll spend upwards of an hour designing and customizing a tricked out, uber-girlie sports car in one of her nephews racing games, but couldn't care less about actually racing it. She just likes the design aspect.