1) Live a comfortable lifestyle, free of work, but not a lifestyle of excess - no ridiculous mansions, yachts, helicopters, private jets, etc. Put my stepsons, nieces and nephews through college or pay their existing college debts.
2) HIDE! Once people know you have "fuck you" money, they come crawling out of the woodwork to find you. I might even change my identity.
3) Produce decks of playing cards. Maybe even purchase USPC, if Jarden's willing to part with it. That company's been needing some TLC for a number of decades now.
4) "Serve the cause of justice" in ways that might be questionably legal...
But no superhero nonsense!
5) Create or fund a college that will charge no tuition to those with the intelligence but not the means to obtain an education. Make said college available to adults as well as newly-minted high-school grads. Said education comes with a price - a small percentage of future income is donated back to the school, to pay forward the exceptional deal they received to future generations.
And before any of that happens - HIRE A GOOD ATTORNEY, if not an entire law firm!
As far as those who manage to blow their lottery winnings, kill themselves, etc., it's simple. Being a multimillionaire doesn't come with an instruction manual - and even if it did, few people bother to read these days anyway. Many people indulge their less noble urges, blowing away cash like it's going out of style. "Friends" start coming from everywhere wanting a taste of your good fortune. They buy or create businesses that, due to their utter lack of experience, are destined to crash and burn. They make terrible stock investments. They make ridiculous purchases of property, vehicles, etc. that cost astounding amounts of money to maintain. They practically throw money away in any number of ways.
Make enough terrible choices, and you can blow away even the largest of fortunes.