Visits to friends rarely seen? Swimming (if your pool allows that combo). Playgrounds. Woods. Beaches. Adventure playgrounds (pay to go in).
Don't ask me, I am a failure. Miserable drizzle here so they have watched hours of vids the last two days (but we are shopping and visiting tomorrow, at least). I would take them out, but it's like prising teeth off! DS-10yo went to a friends yesterday, and DD (8yo) is frantically phoning as I type to try to get a friend to come around, while DS (5yo) is trying to staple his fingers together.