The Thomas Cole National Historic Site is seeking volunteers to conduct tours and monitor the galleries at the site May through October. The site is also recruiting guides for its hiking program on the Hudson River School Art Trail. The open house will provide behind-the-scenes tours and the opportunity to ask questions about becoming a volunteer. A lecture by artist Thomas Nozkowski will follow the open house. Participants in the open house will receive refreshments and complimentary admission to Nozkowski's lecture. Reservations required for open house. Free admission. Information at (518) 943-7465, ext. 5, or mgavilanes@thomascole.org.