An idea I'll never get around to, because I've had it for about 20 years, and you can have if you like, is along the lines of your party boat. I was thinking of an old aircraft carrier conversion, with a helipad, mini-golf course, large pools, maybe even some carnival rides, like a roller coaster. Tennis courts, basketball, even an ice rink would be possible. Bungee jumping? Sure, why not? The carrier flight deck gives you more room, literally(!), for all sorts of things.