The aptly named TRIO — Liz Donaldson, David Knight and Carrie Rose — will charm you on the twenty-THIRD with music in THREE-quarter time. As always, a beginner lesson precedes the dance at 2:45; music from 3:30-6:00. No partner required. Admission is $10; half-price for full-time students. Please wear shoes that will be kind fo the historic ballroom floor.