I try to think about what I probably would be doing. They catch up on cleaning or aspirations, maybe hang out in the backyard, swimming and playing. Sometimes they'll go picnic and fishing or camping for the weekend. They may have a house party, or keg party. My teen sims may hang out in their room playing video games or spend all day on the phone working up their friendships. If it's my rotational save, my sims will visit their family members and work on their relationships with their siblings, parents, cousins, or nieces/nephews, etc.