I get what you mean. Send the kids off to the park, or library, etc., and they just disappear at the curb (like when they go to school) so that the parents can be alone at home. I think that would be a great idea! :) If you live in a neighborhood that has a kiddie park nearby in the public areas, you can send them there to play. Too bad we can't edit the public areas to add objects for all Sims to enjoy and give them something to do other than grill and eat food. Hopefully future neighborhoods will provide more new venue types and come with more or bigger lots that we can build to suit.