You have $20 million dollars and one year in which to spend it. Any investments you make with it have to pay out within the year, and no crazy workarounds or loopholes.
How do you spend it?
[ETA: You can keep things you buy with the money, but not things you buy as an investment. So, house you live in? Yes. House you buy to sell later? No. House you buy to live in one week a year in pretty vacation spot? No.]