One hour of quiet concentration in any business can be worth two hours of normal working time, according to the management of a Denver business. Gary Desmond, an owner at Hoover Berg Desmond (HBD), a $30 million a year architectural firm, said that Interruptions were their biggest enemy of creativity, and the firm's large, open offices, didn't help matters much. So, Desmond came up with the idea to have a quiet hour. Every morning from 10 a.m. to 11 a.m., no one at HBD including the principals, may communicate with anyone else inside or outside the office. "Basically, we're sitting at…