(Logo, 6 a.m. Sunday - 6 a.m. Monday ET) What better way to begin a new month – especially this month – than to revel in a 24-hour marathon of this 1995 character study, starring Elizabeth Berkley as a small-town dancer who comes to Las Vegas to ride a dream, and a pole? Gina Gershon plays a Vegas headliner who takes Berkley’s Nomi under her wing (among other places), in a story that mixes the backstage rivalry of All About Eve with the sexual subtlety of The Opening of Misty Beethoven. There's a good reason to take full advantage of this all-day bacchanal of beads, bangles and bosoms: Written by Joe Eszterhas, Showgirls is the sort of movie that has to be seen a dozen times or so to be believed. And even then…