Raspberry Pi Zero: the $5 computer
When I see $5 all I can think about is a massive cluster of these working together with something like Apache Mesos (http://mesos.apache.org/). The Raspberry Pi Zero, due to low cost, low power requirements (Around the 160mA mark (0.5/0.7W!) and small form factor, could be the future of data centres.You could literally build a 100Ghz machine for $500.