...if time/money was not an issue, and you were finished with all your current projects?
Here's my list, from tamest to insane...est?
1. Flying Machine: Probably an ultralight like a FLPHG, since they don't require licenses and other bullcrap in the US.
2. Self Sufficiency Center: A place with everything needed to survive comfortably, without relying on others.
3. Fabrication Center: Machine shop with things such as a lathe, CAD/CAM mill, foundry, welder and press brake.
4. Exoskeleton: Capable of functioning as both a submarine and a spacesuit, and protecting user from harsh environments.
5. Jetpack capable of VTOL with folding wings that can transition to more efficient horizontal flight, basically a combination of this and this.
6. Flying Submarine with enclosed cabin that does not require scuba gear to dive.
7. Orbital Spacecraft (perhaps also functioning as a flying sub?)
8. Flying City based on Buckminster Fuller's "Cloud Nine" idea.
Sure, the things towards the end of the list might sound a little crazy, but I'm sure I could accomplish them with enough time and space. That's why my current project is to obtain those things.