Most people start on their New Year's resolutions in the clear light of January 1. Over toast and black coffee, we swear to clean up our acts after having spent New Year's Eve engaged in that one last, decadent hurrah. Today we eat, drink and are merry, for tomorrow we diet. Right? Well, the folks at 24 Hour Fitness, the national chain of fitness centers that, true to its name, stays open 24/7/365, have another humble suggestion. You can get a head start on your plan to shape up in 2004 with their free workout days from Tuesday, December 30, through Thursday, January 1. Just think how much more energy you'll have for the New Year's debauchery if you've gotten in a good sweat during the day. Twenty-four locations in the Houston area. Call 1-800-204-2400 or visit www.24hourfitness.com. Free.