How did George Takei get so good at the internet, let alone at real life? His Facebook page, a sustainable hilarity generator, might be the last good reason not to quit Facebook. Jennifer Kroot’s doc delves gaily into the backstory, finding clues in speeches he’s made: Takei talks a lot about looking out at life from behind barbed-wire fences; eventually, in that same super-smooth baritone, he sings “Don’t Fence Me In.” So this is what it means to be the Japanese-American boy whose family was interned during World War II; the TV starship helmsman who worked his way up to movies and to captain; and the once-closeted gay man who came out to rebuke Arnold Schwarzenegger’s 2005 same-sex-marriage veto — with dignity, optimism, impish good humor, and essential help from Howard Stern. Kroot’s film, co-directed and edited by Bill Weber, gathers telling moments with Takei’s husband, Brad, and with his best-known co-stars. Shatner seems like the jackass Takei takes him for; Nimoy seems supportive, if not wholly effusive; other colleagues seem proud of their friend for doing so much more with his post-Trek years than anyone could have thought possible. Those curious enough to watch a whole movie about Takei may well be familiar already with the ground this one covers, but why not have a fond monument and fan-appreciation keepsake, aside from the one that’s already on Facebook?