Water Sports Park
A huge water park of your own, for up to 60 people at once! Great for people with their own pond and just under $80,000 in disposable income. Still, it's nice to dream this would be the coolest thing for a kid (or grown up kid) to have in their backyard.
It features modular components that can be put together in different configuations. You could just buy the single pieces as well. You need to have at least 8.2 feet of depth in water to use this thing, mostly for people diving or faling off of it.
It has an ActionTower you can climb and then jump off of, a balance beam, a huge "Katapult" to launch people from, a high jump, long jump, slide and much more.