Business at the Denver Department of Excise and Licenses has been booming since medical marijuana centers were added to its task list. But director Tom Downey and his dedicated staff have done their best to make any wait pleasant. In 2011, Downey not only put a Westword rack in the waiting area, but he installed a frozen-margarita machine, too. The latter lasted only a week, but the frozen-yogurt machine he added last December has done much better. There's just one problem: Department employees are so efficient, customers barely have time to pick up their spoon and dig into the treat.