- I would buy me a house (or two (for backup), depending on the amount of money). Rent is usually the highest spend in a month.

- I would set apart some money for food for the rest of my life. I know more or less how much I spend on quality food per month. Multiply by 12, and then multiply for the number of years that assume you're gonna live on earth. Food is usually the second highest spend in a month

- Do the same as above but for bills (e.g., electricity, water, gas, internet, transportation)

- Do the same as above but for everything else (e.g., health insurance, clothing, furniture, travelling, etc.)

- With the rest of the money: invest 80% of it, enjoy the 20% left

And then you have days that last 24h just for you! Sleep as much as 9h/day, do tons of exercise to stay fit, have fun with friends and family, finally dedicate countless hours to that topic of yours (e.g. operating systems? poetry? carpentry?) instead of just dedicating a couple of hours during the weekend.

That's what I would do with tons of money. It's all about time at the end.