A recently released scientific poll by a reputable organization (OK, so it was me asking my roommate) has shown that to the average American, the only thing more boring than a documentary film is bluegrass music. So, a documentary about bluegrass would rank only slightly above accidental arm amputation on the fun scale.

It is easy to see how “Grateful Dawg,” a film chronicling the relationship between the Grateful Dead’s Jerry Garcia and mandolinist David Grisman, could be the perfect setting for an hour-and-20-minute nap. But despite its tendency toward shameless self-promotion, “Grateful Dawg” is surprisingly interesting.

The film, directed by Grisman’s daughter Gillian, is half concert footage, half interviews with the duo and those closest to them. This format works well; the constant weaving of music with dialogue keeps the audience’s attention. The movie covers Garcia and Grisman’s entire collaboration, from their first meeting at a Bill Monroe concert in 1964 to their recording of a children’s album before Garcia’s death in 1995.

Despite the plethora of historical tidbits, the focal point of “Grateful Dawg” is the live performances of the Garcia/Grisman Band, most of which came from a show at San Francisco’s Warfield Theater. Unlike most films centered on concert footage, “Grateful Dawg” presents only songs in their entirety; the audience is never offered short snippets of assorted songs. This works to the film’s advantage, especially during the band’s original tune “Arabia,” a 20-minute epic that rivals almost anything Garcia did with the Dead.

The musicianship of Garcia and Grisman is inspiring in these live performances, even to those who don’t appreciate the subtleties of bluegrass. The electricity between the pair is extraordinary, revealing the joy Garcia experienced from playing simple, acoustic music.

“Grateful Dawg” also helps the audience understand the bluegrass roots of the Dead, an influence often lost behind the band’s wall of sound. This shines through in Garcia and Grisman’s stripped-down take on the Dead’s classic “Friend of the Devil.”

The film’s interviews, however, are less than stellar. As the film wears on, the gratuitous self-praise becomes obnoxious: Garcia praising Grisman, Grisman praising Garcia, and everyone else praising how great they were together.

The film seems to skirt issues like why the two, estranged for most of the ’70s and ’80s, never spoke to each other for 15 years. Also, in focusing on Garcia and Grisman’s musical collaboration, “Grateful Dawg” never explores their personal relationship. While this deficiency does not ruin the movie, it does make the audience wish for more in-depth footage.

“Grateful Dawg,” while obviously made for Deadheads who lust after any new piece of the Garcia legacy, is accessible to anyone with an open mind and an interest in music. Though the project would probably work better as a condensed hourlong TV special, the incredible concert footage makes up for these minor flaws. If anything, the film promises to bring the whole “big hair, bushy beard” look back into style.