When I first started playing with the Raspberry Pi I thought it would be a great tool for teaching Computer Science and Design and Technology, but then I thought wouldn't it also be wonderful at the other extreme. Where children and possibly teachers have no computer knowledge at all.
Think about it. It plugs-in, boots and goes to a menu screen. Children use a large Tracker-ball to navigate around and all this for under £100. Imagine Interactive books, Colouring pages, videos and a whole host of other materials that could be put on.
There's no need for Multitasking, networking or anything complicated. If the program crashes, switch off and start again. The great advantage is that the Screen and Raspberry Pi can be kept out of the little one's reach and just the tracker-ball needs to be touchable. All you need is a cheap DVI Monitor, Large trackball and a Pi! Children love Sandbox style play and in classes they could click on an Avatar of themselves for personal settings or it could literally be a sandbox with no set-up at all.
Open Source Linux Software example - http://gcompris.net
There's quite a good selection of Linux software already available and if we developed the tools, interactive books could be developed very quickly indeed.