In the dense woods of Prince William Forest Park, a man is missing. It's about 9 a.m., and a cadre of roughly 20 to 30 volunteers with the Virginia Search and Rescue Dog Association and Shenandoah ...

Sponsored by the National Park Service. 1 p.m., Visitor Center, Prince William Forest Park, Park Entrance Road, Triangle. Free; reservations required. 703-221-7181.