Bitcoins are a completely anonymous digital currency that can be converted into real cash.
And most interestingly, you can use your computer to “mine” them.
It’s something akin to prospecting for gold, except now you’re hunting for 64-digit numbers. By having your computer repeatedly solve puzzles, you’re competing with other miners to generate the number that the Bitcoin network is looking for. If your computer generates it, you receive 25 Bitcoins.