If you have a sweet tooth and want to be a part of history, you may want to head for Yerevan, Armenia, next month.  That's when the world's largest chocolate bar will be broken up and handed out to candy aficionados in the capital's main square.  The oversized item was made by the Grand Candy factory of all natural ingredients, including a 70 percent cocoa content.  The bar is 224 inches long, 110 inches wide, and 10 inches thick.  It weighs 9,702 pounds and was certified as the world's largest chocolate bar ever by officials of the Guinness Book of World Records in a ceremony on September 11.  It was made to commemorate the company's tenth anniversary and will be taken apart and handed out to people on October 16.