Oh, carbon nanotubes, is there anything you can’t do?  Researchers at the University of Illinois Urbana-Champaign have come up with a radio, all of whose reception components are made of carbon nanotubes.  This is pretty much just a proof-of-concept, no one’s going to be mass-producing nano-radios anytime soon, and the actual amplifier and headphone jack can’t really be scaled down, limiting the lower size limit. 

What it does show is that nanotubes can be grown in arranged structures and the conductive properties are good enough that they may be a suitable replacement for silicon.  This is good news for solar manufacturers worried about a silicon shortage.  Not to mention it’d help with that pesky ewaste problem.  Listen to an interview with one of the researchers here.