(http://media.cmgdigital.com/shared/img/photos/2015/02/26/58/42/tornado_1.jpg)
Tornado Tower next to the BOK in T Town. May house a severe weather museum and or offices. First thing that came to mind. I think it's missing a polercoaster. ;D
Yeah, I forget where the concept came from (probably a competition), but there was a brief movement to actually get it built. Haven't heard much from it since though, so I don't think they found enough interest. Or maybe an engineer killed the dream. ;D