Rain barrel workshop. April 8th, 7:30 - 9:00. Come to this workshop and make a rain barrel to collect rainwater to use in your yard and garden! Cost: $50 per barrel - two barrels per household limit. PRE REGISTRATION IS REQUIRED. Click here to register, or see the full list of rain barrel workshops. Williamsburg Middle School Cafeteria, 3600 N. Harrison St. Arlington, VA 22207.