Man, if I had the resources and potential free time like you...
1.) Do "that thing" you always wanted to do but never could. For me, "that thing" I want to do some day, hopefully, is restore a '67 Mustang Fastback, built from scratch, learning every step of the way. Welding the frame to laying the final clear coat. I work for a very large and popular automotive performance company that caters to that particular car model's market, so I learned a lot from work and by way of owning a "modern" version of said car.
2.) Travel to places that aren't just "decent", as you said. I would take the plunge and visit non-tourist destinations of storied countries. Hike the mountains in Nepal, stay in a village in South America (with security, of course), visit Tokyo and roam the city for 2 weeks, learning the real 'scape of the metropolis, not the tourist spots.
3.) This might be cheesy as fuck, but I'd do it: Find someone, a family, a guy down on his luck, a suicidal or clinically depressed person, and just turn their life around. Get them professional help, mentor them how to be successful, get them a set of wheels, pay their first 6 months of rent. Bonus points for finding someone with a serious physical ailment or disfigurement and helping to finance their cure or reconstruction, e.g., a war veteran missing arms and financing a nerve-controlled prosthetic (they exist, now).
4.) Reserve a spot on Virgin Galactic. Self-explanatory.
5.) Learn to fly. It's freeing as Hell, never gets boring when learning, and makes for great pick-up lines and "let me take you up there" hits.
6.) Buy some acreage in Hawaii and build a seasonal home. Shit's surprisingly cheap, depending on location.
7.) Challenge yourself through experience and physical demand. This may be complementary to that "travelling outside of tourist places". I would love to hike the Appalachian, summit the mountains above Lake Moraine to take night sky pictures, or stand on the rim of a volcano.