It's Friday night, and a few dozen folksa mix of senior couples and gaggles of curious college kidshave paid the eight-bucks admission to the Casa Loma. Once upon a time, this grand old ballroom with its majestic wooden dance floor5,000 square feet of tongue-and-groove honey maple that "floats" atop an inch of gentle-on-the-knees rubberplayed host to rug cutters from across the Midwest who grooved to live sets from the likes of Benny Goodman, Bill Haley and Ol' Blue Eyes. Nowadays the Casa Loma only operates as a true ballroom on Friday, with the occasional Saturday-night swing setbut oh, what a night it is. The lights, the big band, the mix of swing, waltz, cha-cha, foxtrot, tango and rhumba classics. If you squint just right, you might convince yourself that you see a cigarette girl working the far end of the room. And if you need some extra help in the sight-blurring department, the drink prices seem like they haven't changed since the day the music died.