Ah, the thought that has probably crossed everyone's mind at some point, and what would I do? Probably the same like "most", enhance your living standards a bit and get to enjoy your life.
"If" I'd win, I'd totally buy myself a flat somewhere cozy in my town, not too big, just a nice flat with good internet and low rent costs, just find a way to live cheap. I'd then stock up on some good and fresh music and computer equipment, and just start recording things as often as time and energy would allow with a rather relaxed economical life situation. Quit my job, try to start a new career with either video or music, get a cheap car to get to and from places, and last but not least, spoil friends online that has taken care and looked after me and my well being.
There's been many situations with broken tablets, computers that needs to be fixed, or just in general "money problems" that I wish I could've done something about to help them out. I know that if I'd be without something like a working computer I'd get restless out of my mind.
Some money would be good, a lot would be even better.