Open-source, low-power bitcoin miner that is relatively cheap. It's hash rate is respectable given the small investment to run one. But, the chance of siccessfully mining a block is like winning the lottery. One did just mine a block, so it can be done, though. 

 Hmm, for just $150? 

 And, just pennies a day to run. It claims to be plug and play right out of the box. Pretty tempting.