(Boulder, CO) -- A study by the University of Colorado's Humor Research Laboratory ranks Portland among the nation's "funniest" cities. The study places the Rose City fifth among the 50 funniest cities in the U.S., based on the research lab's "Humor Algorithm." Among the criteria used in the study are the number of comedy clubs per square mile, frequency of visits to comedy websites by the city's residents, and the number of famous comedians born in each city. Seattle is ranked tenth on the list, with Chicago coming in first.