Archeologists have found the site of a Colonial American theater that counted among its patrons George Washington and Thomas Jefferson. Hallam Theater was one of the largest buildings in Williamsburg during Colonial times and was a defining part of its social life. The outline of the theater was discovered three weeks ago by staff of the Colonial Williamsburg historic site. Directors said the find fills one of the largest remaining gaps in Colonial Williamsburg's re-creation of 18th century life and could lead to a reconstruction of multimillion-dollar proportions. The Hallam Theater played a large and sustained role in Colonial life after its opening in October 1760. It showed the latest London plays.