These days robot-loving Japanese are tinkering with screwdrivers and motors instead of heading to the beach or hot springs during the holidays. Tokyo's major store devoted to robots, Vstone Robot Center in the bustling Akihabara electronics district, sells robots of all sizes and shapes, including the tiny scuttling Robo-Q from Tomy Co. and the Pleo animatronic dinosaur toy from Ugobe Inc. of the U.S.