Fukubukuro (福袋; lucky bag) is a grab bag filled with random items and traditionally on sale for a substantially discounted price on New Year’s Day in Japan. Thousands of Japanese shoppers would line-up early morning on January 1st to hunt for the goodies at department stores and various shopping outlets.
According to Wiki, Fukubukuro was originated from Ginza’s Matsuya Department Store in late Meiji period (1868-1912) and has since become a widespread custom in Japan. The practise was probably first used to offload excess merchandises, but has now evolved into marketing and branding campaigns.
The items in the Fukubukuro is not quite as random compared to early days… lots of the lucky bags these days are themed accordingly (gadgets, apparels, toys etc) and sometimes offered by a particular brand. The shoppers have a good chance of getting what they want, or at least not totally unwanted items.