In primary school we had a robot turtle attached to a BBC Micro with a long cable which trundled around the floor drawing wonky shapes. At the time it was one of the most amazing things I'd seen - and was probably similar to, if not exactly the same as this: http://www.classicacorn.freeuk.com/8bit_focus/logo/logo.html
Later, in secondary school, I remember amazing our teacher by getting the Acorn Archimedes we had to produce multicoloured spirograph-like patterns.
Being able to type something - and then the computer actually going and doing it (or not) was both frustrating and fantastic, and left me with a lifelong interest in programming and learning new stuff.
Thank you Seymour.