At first I'd do the same as pretty much everybody else, pay off my debts and my family's. Give them each a certain amount so they'll be set for life. Donate some to charity.
Once all of that's settled, I'd probably put most of what's left in the most secure account I can find, then spend a couple of years traveling the world. After that, I dunno. Build a house somewhere and do whatever I want to do with my life.