I wouldn't tell anyone that I had won, and just slowly spend my winnings treating my family & friends to things. Like buying a round or two on a night out.
Basically the same, i wouldn't want to flaunt my wealth too much, too many people would want to be your "closest friend".
I'd Buy a nice house for each of my family members who aren't sorted with one for themselves, perhaps with a couple of extra thing's here and there.
Since i'm a lazy ****er i'd hire a good personal trainer to help motivate me to get that killer body i've always wanted.