The Green Salem Business Challenge is holding a three-part event and workshop series to help businesses learn from one another, share ideas, and access resources on how to become more environmentally friendly. The program begins Sunday with a free screening of the movie “Deep Green” at 10 a.m. at Cinema Salem in the Museum Place Mall. The movie is a documentary by Matt Briggs that focuses on solutions to global warming. Doors open at 9:30 a.m. and free coffee will be provided to the first 50 attendees. Now beginning its fourth year, the Green Salem Business Challenge seeks to spur businesses to follow environmentally sound practices and to recognize companies that do so. The series will run through next March, when the 2013 challenge survey opens for participation.