Figure out how much you really have after taxes, fees, other reductions, etc. Keep it in a safe bank account (i.e. the bank will not become bankrupt and your money will disappear; no matter where you keep it, make sure it doesn't vanish) Then sit down and figure out what you want to do. Others have already provided a comprehensive guide to immediate tasks. I think it will help to define a purpose for this money. Your modest living should help greatly; just make sure you don't take purely financial risk with the money (like becoming an investor disconnected absolutely with what he's investing in).
Some personal suggestions of mine include starting another company that you have passion to start and fund. It seems that you won't waste money, but it goes without saying to start as though you has no money at all. If you start anything whether it's a non-profit or company, start immediately with what you need. Ask if you can start with the least you have. Read REWORK by 37signals. (this book will provide invaluable experience) Read Getting Things Done by David Allen. Not only will it help to organize yourself, but refocus yourself on a 50,000 feet level and realize what you want to do with your life. The book can prompt internal self-actualization, but you have to be the one to figure it out. (though their workflow coaching can help setup your system for the first time, you can do it yourself too) Some of this advice, you probably know already, but this can be a refresher.
Ask yourself questions! Feel that you want to help other in your community? Do that. See an incredible opportunity on the horizon? Do that. Work with what you have a passion for.
I hope others on the internet and I have been able to provide sound ideas for what to do. Whatever the case, you already came this far. I wish you the best of luck in what you plan to pursue, and hopefully you'll be able to benefit our world and yourself. Make sure that you make the decision you know are the best for you. Personally, please use the money constructively...help someone with it if you don't know what else to do after making sure you have enough for the rest of your life.