In John Mitchell and Jeremy Kipp Walker's The History of Future Folk, the only thing that stands between the human race and total annihilation either by alien virus or interstellar warfare with the planet Hondo is some guy playing folk songs in Brooklyn. We're not doomed though; don't worry.
In addition to being a pretty sick banjo player, the guy singing folk songs is a general in the Hondonian army. He's called Trius (Nils d'Aulaire), though his Earth wife and daughter know him as "Bill" and "Daddy" respectively. As a highly ranked officer in the Hondonian army, Bill has a little bit of sway to call off the potential attackers. At least he used to.
Bill first came to Earth on behalf of Hondo to release a virus and wipe out the whole human race. After he crash-landed in the New York countryside, however, he stuck with that mission for exactly as long as it took him to hear music for the first time over the PA in some big box store somewhere. It turns out there's no music on Hondo, and Bill was so transported by this novel arrangement of sounds that he abandoned his mission, married an Earth woman, and started singing folk songs about his life on Hondo in bars in Brooklyn.
If you can hang with all that, The History of Future Folk is about as charming as movies get without ever once becoming saccharine. Calling to mind a combination of the "sweded" films in Michel Gondry's Be Kind Rewind and a particularly surreal episode of Flight of the Conchords, The History of Future Folk plays its premise straight, opting for sincerity instead of easy irony.
The several concert scenes are crucial. The film opens with a solo d'Aulaire tentatively picking out "Impossible Dream" in front of a skeptical audience while clad in Hondonian battle armor. It's a song about his cosmically on-hold desire to get home again. With this scene's shoving together of the commonplace (the melancholy of being far from your home, not to mention that of the ambitious musician at the open-mic) with the absurd, we get a clear framework for how the entire film works.
The History of Future Folk comes across like the product of a group of people having way too much fun taking a silly premise seriously, and it's infectious.