Denver's major cultural institutions offered free admission all day on December 31, but that was just a taste of the big, big fun still to come. By 11:58 p.m. on New Year's Eve, the 16th Street Mall was one mass of happy, freeloading humanity, eagerly awaiting the fireworks that were set to light up the D&F Tower. And for once, a show lived up to its advance billing: Within seconds, the mall exploded in a blaze of lights and sights and sounds, wrapping 200,000 spectators in smoke and an incredible feeling of well-being. Everyone got such a bang out of the Mayor's Millennium Celebration that it more than made up for the bust of the previous New Year's Eve -- and Mayor Wellington Webb was so moved that he promised a repeat performance next year (if sponsors step up to the plate, that is). We say: Party on, Denver!