I actually had a talk with this with one of my friends recently, although we were talking about 50 million.

With a billion?

Get a bunch of fast cars, like 6-8, and give all my close friends that I knew BEFORE the money came in access to them for some sick road trips. (Aston Martin would be first, GTR second, a nice american muscle one). Id also get a "sleeper"...A car with a shit, semi rusted body, but have 50k of mods on the inside just for laughs.

Treat my friend that I knew before the money (this is always key for me) to a insane vacation.

Home gym.

Insane gaming room with a strong PC and all gaming consoles.

Buy the house I grew up in from my dad and re-doing it to my taste, with the giant garage for my cars.

Once all that is done, go see a financial planner to make sure i never have to worry about money ever again with the lifestyle I have. I would assume thats about 100-200 million and I can still do whatever I want, whenever I want. Then spend my time giving away the rest and helping the world.