OK, here's another one that's so cool! :) First we had a single-electron refrigerator. Now we have the world's first heat transistor.

Physicists in Finland and Italy claim to have built the world’s first "heat transistor" in which the flow of heat between two electrodes is controlled by a voltage applied to a third lead. The flow can be increased, decreased or even switched off by changing the voltage -- in much the same way as electrical current is controlled in a conventional transistor.


Very, very clever!