Short post, to highlight a great application of open source: school text books. Long a source of massive profits for publishers, primary and secondary school texts have been available on an open source basis from the CK-12 Foundation, Wikibooks and MIT for a number of years now, but with mass acceptance of e-readers and tablet computers now on the horizon, open source texts are becoming a viable option for schools.
What's it worth? Well, 7M children are in education in the UK at any one time - say the average state school spends £25 a year per pupil on texts, that's £175M per year. Clearly there's a capital charge for the computing devices, but I question how long schools will be buying conventional PCs for anyway - surely the PC is as troubled in the education sector as it is in the home and, increasingly, in the workplace.
One for the Government to consider in its spending review, I think. Incidentally, the business case for "Sound and Vision" in the Netherlands is partially based on the economics of replacing paid-for education material with already paid-for video and audio from the Dutch PSBs.