It's fun to think about. Like mentioned above, I know all flack about the odds of winning being worse than getting hit by lightning 10 times in a row, but that's a lot of zeros.
First would be to do my damnedest to stay quiet. Luckily, I don't have a large group of friends, nor do I have a big family of aunts and cousins and such. Not that ones might come out of the woodwork if they found out, just there's not an immediate issue.
Then, interview a few law firms in another city to find one I think will be OK to setup a blind trust or LLC to accept the winnings on my behalf and not have my name out there. Work with accountants and tax folks to make sure everything's paid and appropriately distributed in several banks to cover FDIC insurance. Figure for the first few months, a 1 or 2 % return is fine until I get stuff sorted.
Then pay off all my bills, all my mom's bills and all my sisters bills. Give my mom and sister enough to live comfortably for the rest of their lives. Setup a trust for my son so he can finish out school and, basically, do whatever he wants afterwards. I have a friend or two I'd probably pay their mortgage or something to help them out, but figure out how to do it anonymously. (The law firm should be able to help with that)
The accountants can help me figure out investing. One portion in low risk to take care of the rest of my life, some in mid-risk, some in high risk. I'd kinda want some to play with the market it a bit myself. Doing research, making investments, looking for trends, etc. Not that I would ever need that much money. We'd have trouble spending a 1% yearly return on the initial money, but having more gives me the ability to help more people.
From there, it's figuring out what to do. A new house outside of town with some acreage is top of the list. With a huge barn to store every car I've ever wanted. Buy at least a new car for the wife, the son and a truck for me. Gut my current house and have it rebuilt to either rent out or sell off.
Then it's probably some type of extended travel for the wife and I. Like a year of just picking a spot, buying first class passage and go. No real agenda other than what strikes our fancy for the day. I assume that will also lead into a bit of car buying from other countries and having them shipped to the house.
Maybe spend a year going to every F1, IndyCar and Nascar race with my son.
Once we get that out of our system, it's just investing to do charity work. There are a number of ways to make a difference in people's lives, and I'd like to do that. I always thought buying a number of inexpensive new cars from a dealer and setting it up that the title stays open until I give it away. Something like 10 Honda's or Chevy's that are inexpensive to run and insure and have a huge dealer network for any warranty stuff. Work with an insurance company to make sure to have their insurance paid for a few years. Put a few gift cards in the glove box (with like $10k on them) for things like groceries, gas and general items. Then, randomly give them out to the homeless or beggars on the street. Not sure if I would do it, or hire the first few folks to help me do it. Basically, try to positively change people's lives by giving them the tools to start.
In addition, come times like Thanksgiving or Christmas, buy out every Thanksgiving meal thing at the grocery store, buy everything on a wish tree, buy all the bicycles needed for any local bicycle drive, buy all the coats for kids, etc. I'd figure out how to do it anonymously so it's always a surprise and doesn't fall into being "expected" every year or something.
Although, it would be tempting to see if I can influence the federal government. A half a million dollars to every congressperson might get me some sway to get things done......
Edit: For my car collection, it would probably be very weird. Of course, I'd have a Porsche or two, maybe a Ferrari or two, but most of it would be collections of oddness. Every Si made since the beginning. A collection of hot hatches from the '80's and '90's. A full collection of micro cars (maybe start the micro car museum up again). Maybe a few pre-war cars.
-Rob