The amount of open source applications for the Raspberry Pi is impressive. People have been able to make the unit do everything you can think of. Even developer Mojang released a version of Minecraft for it. (I actually have two myself with one serving as a GPS enabled NTP server and the other running OpenELEC as a media player.)
Next month Code Club Pro will deliver a full training curriculum and online resources for teachers worldwide to deliver on the initial target of the Raspberry Pi.