MineField is a bitcoin gambling game where you can set your own difficulty. There are 16 minefields, and you can set how much TNTs there are. This also affects your payout.
You can play for free (but you won't win anything), as well as bet from 0.001 BC to 5 BTC. Trust me, it's really addictive.
As with all gambling games, over the long run you will lose. But you should (a) play it for the entertainment - minefield is fun (b) if you just play it once or twice, you have a high chance of making a bit of profit.
http://minefield.bitcoinlab.org/As always, don't bet more than you can lose.