If you happen to read ACM Queue there is a great article in the Nov/Dec 2007 issue called 'A Conversation with Mary Lou Jepsen' the CIO of OLPC (sorry, I don't have a URL to it) that talks about some of the technical innovations in the product. They did a ton of work to reduce power usage and to increase the range of supported power beyond standard 110v/12v dc inputs. They went with a solid state hard drive so that they could save the power needed to constantly spin a hard drive. The motherboard is behind the screen so it doesn't get hot on a kids lap! That's just a sample; it's well worth reading and is a really inspiring example of getting out of the traditional box to solve a problem that needed solving.