Rather less silly, actually an atomic watch and close to wristwatch size: http://www.ablogtowatch.com/bathys-hawaii-cesium-133-atomic-wrist-watch-accurate-secon

Rather less silly, actually an atomic watch and close to wristwatch size: http://www.ablogtowatch.com/bathys-hawaii-cesium-133-atomic-wrist-watch-accurate-second-1000-years/ http://www.ablogtowatch.com/bathys-hawaii-cesium-133-atomic-... edit: grammar