This third annual formal prom will sail the Potomac on the Spirit of Mount Vernon tomorrow night, Saturday, March 7, in a benefit for One in Ten, the local gay arts organization that produces Reel Affirmations, among other activities. The prom, for GLBT adults, will feature food, music and dancing, a silent auction, and of course, the crowning of a king and queen. Boarding is at 7 p.m. Pier 4, 6th and Water St. SW. Tickets are $50. Visit www.eventboi.com/prom.html for more information.