“Pink Tube of Goo” is one of those good things that happen in the new Denver, where the economy is soaring, the population is booming, and civic self-confidence seems to be at a record high. Art, big and small, is thriving here right now, in museums where attendance records are shattering; around bustling commercial and residential developments, which are using shiny art objects to lure customers; along streets and alleys where fresh murals go up weekly. Much of the progress is due to new money, and growing institutional support for creativity, manifested in things like the new art space Understudy, which is funded by the nonprofit Denver Theatre District using ad revenues from the giant LED signs it has put up around our rapidly infilling downtown.