I’ve got fond memories of RISC OS from my school’s room full of Archimedes. I spent a a fair bit of time designing and failing to build a text adventure in Basic, while my teacher tried to get us to learn how to use TechWriter. Best feature was being able to drag a slider to create a RAM disk.

Amazingly you can still buy a copy of TechWriter 9.1 for £85! http://www.mw-software.com/software/ewtw/ewtw.html