The Whole World In Your Hands

As a millionaire, there are many devious plots you could enact to gain supreme rule of the universe. You could try to buy a mercenary army and have them attack the rest of the world. Perhaps you'd like to buy stock in a company, giving huge payoffs (hopefully)?

If you were really evil, you might want to assassinate the leader of every nation, but that'd probably be a very difficult thing to do...