I was chatting in IRC a few days ago when someone told me about 'Bitcoin'.
It's basically a de-centralised e-currency. You can earn these 'Bitcoins' by either using your computer's spare CPU/GPU cycles to work together in 'pools' of computers to solve a puzzle. Coins are then divided between everyone in the pool based upon how many cycles they put into the pool.
Of course, this isn't the only way of earning bitcoins, you can also do jobs for people just like any other currency. Because it's de-centralized, no cut is taken and coins are transferred directly between people.
I'd like to hear people's opinions on this, because I'm not entirely sure if it's worth it or not.
Here is a link to their site where you can learn more: http://www.weusecoins.com/