I'm a big science fiction fan. Many of the current SF authors use nanotechnology extensively in their stories. Just about anything imagined can be accomplished with nanotech. Just read any books by Neal Asher or Charles Stross and you'll see what I mean.
What's amazing is, these ideas aren't so far fetched. Scientists are getting closer and closer to developing real machines that operate on a nano level.
Here's an article in The New Scientist on one such machine. It's a nanopore used to sequence DNA strands in microseconds.
You can watch a video of a computer simulation of the machine in action. They haven't actually built the machine yet but say that they have proved the machine will work and they do have the technology to build it. Amazing.