While doing research on computer history I came across this ancient BBC documentary series from 1981 called "The Computer Programme." The video quality is horrible, really jerky (think Max Headroom), but the show is priceless. It catches computers just as the first PCs like the Commodore PET, Sinclair ZX81 and the BBC Micro were entering the market and home users were starting to write their own BASIC programs. A real piece of history from 30 years ago.
Incidentally the website that is indexing the documentary topdocumentaryfilms.com is very good if you like docos.