Public Service billboards all over town
“If you’re being passed on the Right
You’re in the wrong”
“The great thing about Science is that it’s true
Even when you don’t believe in it.”
“If you’re not happy with your life,
you might reconsider listening to people
who are paid to tell you how angry you should be.”
“Contraception prevents Abortion”
and others as I think of them.
Maybe even some public service “these guys are lying to you” TV ads during elections.
I would renew every Doper’s subscription for a year.
I would make an appointment with my ex-real estate broker to have her show me about 100 million dollar houses. Lining up those properties is a royal pain in the ass.
Then I would buy a For Sale By Owner.
Hire expensive powerful aggressive lawyers to concoct and relentlessly pursue frivolous lawsuits against people I consider to be jerks.
I’d be seriously looking at buying a Phoenix 1000.
Wander around the mall, asking random people to call a coin toss. If they lose, they get the quarter. If they win, they get a twenty-dollar bill.
Pink lawn flamingos. Lots of pink lawn flamingos.
I got nuthin, but my friend said he’d buy all the companies he ever worked for and fire everybody. He’s a bricklayer so I assumed that to mean the foreman.
Personally me and all my golf friends would rent Pebble for a week.
NM, didn’t read OP correctly
I’d run an open contest to design the most amazing, incredible, creative, complex mini-golf hole.
Hand pick the 18 winners myself and award each $20,000. Hire architects, landscapers, and contractors and build the world’s most amazing mini-golf course.
Then charge people $1 a round.
On the news today they pointed out that the St. Louis Cardinals baseball club has an estimated value of $518 million. So I’d buy the Cardinals.
And if I really wanted to screw with people, I’d send the entire organization to Chicago and bring the Cubs to St. Louis.
If that should somehow happen, don’t be surprised if I’m found dead somewhere in St. Louis.
Buy a MiG.
I don’t know which model, or what I’d do with it, I just…want one, okay?
Buy the game Glitch from the current owner who is shutting it down.
Rehire the developers and CS staff, add more employees of my own and set up to restart the game, I would obviously have to email all the previous subscribers and offer them a free month to get the ones that are not hard ore fanatics to come back. I would also actually advertise the damned thing. I feel that one reason it is closed down is because it was not advertised enough, in the right venues.
Buy a nice small ship that can hold about 15 passengers [not counting the crew needed to operate the thing] and head off around the world on vacation - I would fly random pairs of friends out to join us as they cycle through their vacation time.
Hire a live in nurse to take care of my Mom so my brother doesn’t need to worry about her while he is off at work. Heck, cut a deal with a financial institution to give my brother an annuity so he doesn’t have to work for the rest of his life.
Hire a secretary to receive any requests for funding to sort through them and allot a million a year in charitable funds.
I’d set up a “gun scholarship” charity, that would pay the complete cost for qualified people who want to get a carry permit and a handgun. Would include lessons, range fees, the permit application fee and once they passed a gun and storage safe. Priority would go to previous victims of violent crime, women, the elderly and minorities.
And a few kilometres west of St Louis, build a twenty-storey-high statue of a croquet ball. Bonus points for including an avenue of flattened trees and buildings leading up to it. 
I’d buy a big empty building and put a walk-through “historical town” section (you’ve probably seen things like it in museums, just enclosed pseudo-streets with cobblestone and fake period stores or theaters or whatnot to either side) in it and rent it out for parties and LARPs and student film projects. I’ve always wanted to do this, for some reason.
I’d design and kit out a really awesome room for my rattery. Tile floor with a drain, big windows, giant cages, natural light, etc.
I’d buy ArenaNet and Paragon Studios so that NCSoft would stop fucking up the games I love 
I’d dress as a bat and fight crime.
I think some people need to actually read the OP. Hell, reading the subject line should already give you a hint of what he was going for, but apparently not to some people.