I'm going to build a ton of race tracks from Mario Kart and a bunch of classic arcade games. I'm kind of hoping you can put glass domes over your creations, because one of the the tracks I'm building was originally in an environmental dome.
I'm also going to build a bunch of sports arenas for soccer and the like. But I'm going to put a twist of wrestling by turning it into King of the Hill with a bit of "Clash of the Titans". It'll be an arena over an oubliette of those shrink pads!