A group of MIT grad students have been working on a guidance system for handheld power tools that leads to far greater precision that is typically achieved with such tools. Their position-correcting tools require rough manual positioning before a computer takes over and adjusts the exact spindle position along a more complex two dimensional path.
In other words, as long as you can keep the tool in the ballpark of where it needs to be, it will automatically be guided along the proper path.
There is great potential for this tech to be developed for the consumer and professional markets. What it does is essentially turn handheld routers into portable self-contained manual CNC machines. You can achieve the same high precision as you would with a full-size CNC router, but without the hefty hardware and space requirements.
Position-correcting technology is being developed with woodworking routers, but the tech can probably work with other tools as well.
If interested, you can download a very detailed paper (PDF) discussing the new technology. The work is also described on a webpage set up by the students (Alec Rivers, Ilan Moyer, and Fredo Durand).
(via NY Times: For the Home Workshop, a GPS for Power Tools)