1HP Blackjack

Start with $1,000 and try to make $1M. If you lose all your money, you cannot buy back in; the game is permanently over. The game renders in a tiny overlay on your screen, so you can still focus on your work and just play a few hands whenever you're bored. You can also easily minimize or drag the overlay around to fit it comfortably on your screen without interfering with your main content. No real money involved.