The comedian first gained exposure from tens of millions of hits on his YouTube page, with songs that dealt with subjects such as family, high school, teen love and, uh, rehab for fictional characters. That led to a deal with Comedy Central and Burnham becoming the youngest person ever to have a special on the channel. He’s returning to Denver for a series of shows at Comedy Works today-Saturday with the unusual caveat of all shows being 18 and up — and the Saturday 6:30 p.m. show being an unheard-of all ages. $25-$80. comedyworks.com