I would probably save a portion of it for financial security (might want to not work for a few years to write books) and donate the rest to various worthy causes. Right now, there's not a lot that I want that I couldn't buy, and the things I most want in my life are things that cannot be bought. A large influx of money wouldn't change things very much.
I think the lottery is an immoral institution anyhow. Societal privilege should be earned, and the greed inspired by the lottery system is unhealthy.