Nitpick: You mean Action #1 Throw in Detective Comics #27, first appearance of Batman, since you’re prepared.
I would take out an ad in every newspaper and post on every website about my good fortune, complete with my name and address. I would then send back any request for money with my new stamp on it
FUCK YOU
I like Kiber’s idea. I’d like to find a way to force big football and basketball schools to cut their sports programs. Maybe something like, “Your school will get my $50Bn estate when I die if you spend only X amount on sports for the next 25 years. And this is my firm of financial investigators who know how to prevent you from getting around this condition. And you can’t tell ANYONE why you’re doing this.” But of course I would make this offer in secret to many, many different schools so that when I do finally die, at best the money is split into tiny amounts for each school.
I couldn’t think of anything until now, but that gave me an idea.
I would manufacture the plagues (except the baby killing, of course, but I’m sure they’d all be fearful that it would COME – and the boils, if that counts as physical harm) SOMEHOW, state-wide, in California. And then somehow convince them that God is angry because they won’t allow same-sex marriage.
With all due respect, I submit Jell-o would be a much better choice. 
As for me, I’d track down everyone who ever ended a job interview by telling me, “We’ll let you know either way by day x a the latest” and then had no further contact with me.*
I’d fund investigations to figure out what job they wanted more than any other. Then recruit them aggressively for just such a position, assuring them the interview was just a formality. Bring them to the most impressive office possible for their industry and get their hopes sky high. End with assurances they’ll be hearing from me in the next day or two.
Then obliterate any trace my business ever contacted them.
*I realize they aren’t obligated to hire me but it always pisses me off when they don’t even bother to send a simple form letter after all their assurances.
I’d fund investigations to …embarass the people who bullied me in public school.
I can just SEE all those fake-ass-motherfuckers come running when it is known I have mad stacks of money. I will take out a full page ad in the paper with a list of names when they come and i can afford to run it for months on end. I can buy as many ads as i want and put them in papers all over the US. I’ll tape them begging, and put it on youtube.
#1 : set aside enough for me to retire on, say a half million.
#2 : eradicate everything by Shakespeare ever. (I frikkin’ hate that guy!)
#3 Ditto Charles Dickens.
With ownership of enough surrounding land and expert designing of the adjacent private roadways and landscaping so as to make it impossible for protestors to pester the clientele. Option: include a “free speech zone” that is (barely) visible and audible from the access route, thickly planted with brambles, thorns, and plants that attract stinging/biting insects.
I’d buy Apple.
I’d allow stores to discount whatever they wanted to of my product, as long as I’d been paid for it upfront. If they lose money, that’s their problem.
I’d also open the OS to allow it to be used on any PC it’ll run on.
I’m sick of the Apple monopoly and nobody does a damn thing about it!
I’d do what Chairface Chippendale tried to do: Use a giant fuck-all laser to carve my name into the moon.
You can come sit next to me. And here’s a book for you.
Move the Yankees to Birmingham, Alabama and still call them the Yankees.
This isn’t something I actually want to do, understand, but it’s a mean thing - buy the film/TV rights to some geek favourite properties, like Firefly (hi, silenus!), BSG, whatever - then hire the shittiest people to make new works based on them. I’m talking people who make Uwe Boll look like an auteur. And that Watchmen cartoon is definitely greenlit!
Otherwise, I’d buy up every golf course in my city, and turn them into pubic indigenous-vegetation parks. The current state of environmental legislation will prevent any new ones being built in the city. Suck on that, golfers.
I would buy the company I used to work at, and then begin firing the team I used to work with, one by one. I’d actually start with the people I lked, and they would get huge severance packages, like never have to work again amounts of money. Then the next round of fires gets less, next even less, so on.
Till eventually no one is left except my former boss and this one VP. Everyone up until now has received at least a decent severance package, so they are still going to be hanging on, waiting for theirs. No one else is there, so they are having to handle the entire stinking cesspool of a company. Customer complaints, service outages, etc.
And then…nothing happens. They never hear from me again.
I’d hire private investigators to locate all the people who made grade school a living hell for me, all the people who bullied me and who physically beat me or hired other kids to physically beat me, and make their lives a living hell. Oh, I wouldn’t hire “Vinnie” to break their legs, oh no, nothing blatantly illegal, just constant, unrelenting legal harassment and annoyance until their heads explode from the stress of it all. Oh, and I’d make sure any current spouses/significant others and/or offspring know what sort of loathsome, sadistic, vile people they all were, how cruel they were, how despicable. Hell, I’d plaster the information across billboards and broadcast it on PSA’s. During the Superbowl.
Buy up every AM radio station between the east coast and the Rockies and change their programming to NPR shows, classical music and jazz.
Okay, that’s definitely illegal and probably costs too much money. Maybe I’ll just fund a mega-mosque in downtown Tulsa.
I’d buy stocks. Sell. Reinvest. Get richer.
And then build a church that would dwarf your mega-mosque.
Mine is a bit different. Use my money to drive the Koch brothers into bankruptcy, and, when they are lying in the gutter, piss on them.
Other things: Buy the San Jose Mercury News, fire all the big bosses, and hire back all the good reporters they’ve fired. Then get them to investigate all the slimy deals the old bosses have done.
Run for governor of California - no wait, Meg Whitman threw her money away on that already.
Buy the Cleveland Indians or the Kansas City Royals and offer $40 million more per year to every player the Yankees go after.
I love the New York Islanders and liked a promising rookie they had years ago named David Volek.
I dreamed of sending out agents to buy all his rookie cards (worth about 10 cents) they could find. I would make a huge bonfire and burn them all except for one. It’d be awesome if the most valuable hockey card was some random New York Islander.