Walden Media has optioned Peter Craig’s family comedy spec script “Relativity.”Story’s set on the eve of a couple’s 35th wedding anniversary. The disclosure of a secret sends shockwaves through the household. Craig’s short film “Nevel Is the Devil” made its debut at the 2006 South by Southwest Film Festival and is screening at other fests. It’s an excerpt of Craig’s feature-length script “Green,” a project that was part of the Sundance Screenwriters Lab. Walden Media entered into a joint venture last summer with Fox to market and release family films.