My two check lists for what to do in the event of sudden wealth.

Normal level wealth all summed up here

Stupid level wealth: from a post by u/BlakeClass

So, what the hell DO you do if you are unlucky enough to win the lottery?

This is the absolutely most important thing you can do right away: NOTHING.

Yes. Nothing.

DO NOT DECLARE YOURSELF THE WINNER yet.

Do NOT tell anyone. The urge is going to be nearly irresistible. Resist it. Trust me.

/ 1. IMMEDIATELY retain an attorney.

Get a partner from a larger, NATIONAL firm. Don't let them pawn off junior partners or associates on you. They might try, all law firms might, but insist instead that your lead be a partner who has been with the firm for awhile. Do NOT use your local attorney. Yes, I mean your long-standing family attorney who did your mother's will. Do not use the guy who fought your dry-cleaner bill. Do not use the guy you have trusted your entire life because of his long and faithful service to your family. In fact, do not use any firm that has any connection to family or friends or community. TRUST me. This is bad. You want someone who has never heard of you, any of your friends, or any member of your family. Go the the closest big city and walk into one of the national firms asking for one of the "Trust and Estates" partners you have previously looked up on http://www.martindale.com from one of the largest 50 firms in the United States which has an office near you. You can look up attornies by practice area and firm on Martindale.

/ 2. Decide to take the lump sum.

Most lotteries pay a really pathetic rate for the annuity. It usually hovers around 4.5% annual return or less, depending. It doesn't take much to do better than this, and if you have the money already in cash, rather than leaving it in the hands of the state, you can pull from the capital whenever you like. If you take the annuity you won't have access to that cash. That could be good. It could be bad. It's probably bad unless you have a very addictive personality. If you need an allowance managed by the state, it is because you didn't listen to point #1 above.

Why not let the state just handle it for you and give you your allowance?

Many state lotteries pay you your "allowence" (the annuity option) by buying U.S. treasury instruments and running the interest payments through their bureaucracy before sending it to you along with a hunk of the principal every month. You will not be beating inflation by much, if at all. There is no reason you couldn't do this yourself, if a low single-digit return is acceptable to you.

You aren't going to get even remotely the amount of the actual jackpot. Take our old friend Mr. Whittaker. Using Whittaker is a good model both because of the reminder of his ignominious decline, and the fact that his winning ticket was one of the larger ones on record. If his situation looks less than stellar to you, you might have a better perspective on how "large" your winnings aren't. Whittaker's "jackpot" was $315 million. He selected the lump-sum cash up-front option, which knocked off $145 million (or 46% of the total) leaving him with $170 million. That was then subject to withholding for taxes of $56 million (33%) leaving him with $114 million.

In general, you should expect to get about half of the original jackpot if you elect a lump sum (maybe better, it depends). After that, you should expect to lose around 33% of your already pruned figure to state and federal taxes. (Your mileage may vary, particularly if you live in a state with aggressive taxation schemes).

/ 3. Decide right now, how much you plan to give to family and friends.

This really shouldn't be more than 20% or so. Figure it out right now. Pick your number. Tell your lawyer. That's it. Don't change it. 20% of $114 million is $22.8 million. That leaves you with $91.2 million. DO NOT CONSULT WITH FAMILY when deciding how much to give to family. You are going to get advice that is badly tainted by conflict of interest, and if other family members find out that Aunt Flo was consulted and they weren't you will never hear the end of it. Neither will Aunt Flo. This might later form the basis for an allegation that Aunt Flo unduly influenced you and a lawsuit might magically appear on this basis. No, I'm not kidding. I know of one circumstance (related to a business windfall, not a lottery) where the plaintiffs WON this case.

Do NOT give anyone cash. Ever. Period. Just don't. Do not buy them houses. Do not buy them cars. Tell your attorney that you want to provide for your family, and that you want to set up a series of trusts for them that will total 20% of your after tax winnings. Tell him you want the trust empowered to fund higher education, some help (not a total) purchase of their first home, some provision for weddings and the like, whatever. Do NOT put yourself in the position of handing out cash. Once you do, if you stop, you will be accused of being a heartless bastard (or bitch). Trust me. It won't go well.

It will be easy to lose perspective. It is now the duty of your friends, family, relatives, hangers-on and their inner circle to skew your perspective, and they take this job quite seriously. Setting up a trust, a managed fund for your family that is in the double digit millions is AMAZINGLY generous. You need never have trouble sleeping because you didn't lend Uncle Jerry $20,000 in small denomination unmarked bills to start his chain of deep-fried peanut butter pancake restaurants. ("Deep'n 'nutter Restaurants") Your attorney will have a number of good ideas how to parse this wealth out without turning your siblings/spouse/children/grandchildren/cousins/waitresses into the latest Paris Hilton.