I would buy property - one larger house in Moscow suburbs, one smaller wooden one in Karelia, both with a bit of land. I would buy new cars for me, my wife and my dad, and renovate our old countryhouse for the sake of nostalgia. I would help my relatives fix minor financial/property issues they have. That would leave me at 7-7.5 mil. I would take out 0.5 mil for fun, travelling and costs at hand and invest the rest in a well diversified low risk portfolio.
I would leave my job the next day I get the money and take 9-12 months off, then would probably go back to working again just so I don't get bored. However, I might do photography instead of returning to office work if my investment portfolio does good and stable.
Fuck. I need to get my hands on those 10 mil.