Today would have marked the 70th birthday of guitar great and Grateful Dead frontman Jerry Garcia. To celebrate, we're kicking off Grateful Dead week with this exclusive clip from "A Birthday Celebration: The Grateful Dead Movie Event," which Fathom Events and Rhino Entertainment will screen tonight at participating theaters around the country. (Details are on the Fathom website.) 

The showing includes a Gracia commemoration directed by Justin Kreutzmann that features Bob Weir and other surprise guests, as well as the 1977 concert film The Grateful Dead Movie, which documents a 1974 concert in San Francisco. Check out our exclusive clip from the film as the Dead groove their way through "Going Down The Road."