Slow Blues lesson and Dance. 7300 MacAuthor Blvd. Glen Echo MD 20812 Lessons & dance ($17); dance only ($12). "All social dances are open to the public, for all ages, with no prior experience or partner required. Alcohol is prohibited on park grounds, and smoking is prohibited in all buildings. Dress is casual, and 'layers' are recommended, because the dance halls are neither heated nor air-conditioned." Heaters & fans. Please visit www.dancedc.com or call 301-978-0375 for more info