The Michigan Department of Environmental Quality website has two videos (viewable on your computer) of mercury evaporation at room temperature. One of a broken thermometer on carpet; the other of liquid mercury in an open dish. These were filmed at Bowling Green University using a UV light and fluorescent background, which makes the evaporating mercury visible. 
Check them out at: http://www.michigan.gov

(Right hand column on the page - Broken Thermometer Video and Toxic Mercury Vapors Video)