Some of these are rather shamelessly copied from others
- Give some to family (okay, this was a given)
- Don't tell anyone except for family and *very* close friends. Probably still lie to friends about exactly how much I inherited, but pay for nice group vacations, make their mortgages disappear, etc.
- Offer 50-100 million to the nonprofit I work for, under the condition that they instantly and irrevocably abolish all of the stupid "auditing procedures" they've put into place over the last few years. Enjoy watching management squirm trying to decide if greed or pseudo-ass-covering is more important.
- Charitable donations -- primarily for education, health research, and environmental causes.
- Advocate and invest/research in clean-energy industries, including nuclear, solar, high-efficiency batteries, etc.
- Travel -- maybe an "around the world" cruise, definitely stuff like Earthwatch travel/research expeditions, visiting all 7 continents, etc. Quite likely look into spending a year or two living in another country as an expat (doing pretty much anything).
- Buy a nice urban penthouse-style apartment in San Francisco or Seattle, my two favorite (US) cities. Okay, we're talking *9 BILLION* here... So maybe both .
- Part of me would want to be a permanent college student... Who only audits classes so he doesn't have to stress about exams, etc.