French watchmaker Jean Jerome created the HDD Watch in 2014 with a successful Indiegogo campaign, recycling 1″ hard drives for the movements.
The idea sprang from a shoop on a watch forum, which Jerome pursued into a full-blown, successful product. Today, you can buy one for €150 (for a silver case) and €180 (black case), with your choice of a steel strap or one made to look like circuit boards.
(Thanks, Zack!)