I've actually thought about this a bit, and I have a plan/fantasy of what I would do if I ever came into that kind of money. There's the usual pay off debts of loved ones, etc. There would still be a LOT left after that, which I would invest somewhere fairly safe to create a reliable revenue stream. This is where it gets a bit more interesting. I am a researcher at a public university in the west. There are a lot of good researchers here who are doing good work, but we're not somewhere people generally think of when they think of a large research institution. If I had that kind of money, I would use it to give anonymous no-strings-attached grants to researchers here. For example, say I learned of someone in the Plant Science department who had some good ideas that were just too risky and they couldn't get funding for that. I would anonymously give them a few hundred grand to explore those ideas as they saw fit. I would love to see my colleagues here not have to worry and fight so much for funding, and if I came into a windfall like that, I would do something about that.