If I had $100B, I would get a heart attack :) This is 500-lifetime earnings for the average US citizen. But easily could be wasted by four generations.
It is a vast life change event, not only for me but for all related to me people. With all those opportunities, many problems need to be reviewed.
I need to secure the money once I get them. Then I'd split it into 2 parts: to build a place to live and to invest in generating constant income.
Investment should be the giant pile, which will generate enough dividends to increase capital and cover all day-to-day expenses.
When money becomes no issue, the next step is to make life pleasant & longer.
I'd buy an island and build a small community there. On the island, I'd set up a leisure & working environment for residents.
I would free up enough time to be with family. Together we could travel worldwide, learn new stuff, and have unique experiences (including extreme ones).
Spend more on a healthier lifestyle to live longer. I would invest in medical research to help me with it as well.
Would start a project where I could deal with challenges. I need to have something which will wake me at night ;)
Organize regular investment in charity organizations and projects/companies to solve the next humanity's challenges. Need to help Earth to survive.
Some dividends will share with relatives and friends.
Would I be happier? Sure! And I'd like to make it as long as possible :D