Dark Star is a 1974 science fiction/comedy film, the first feature film of John Carpenter. At about 21 minutes in there's a delightful little musical instrument. This is the 2nd science fiction film I can remember seeing that includes surfing in the plot.
Watch it online:
Moria gives it 4 stars and says, "The film has this sense of deadpan humour that just sits there and keeps building to the blackly hysterical." The New York Times says, "Even in the glow of hindsight, "Dark Star" doesn't contain many indications that Mr. Carpenter is a director about to turn the world on its ear." Roger Ebert calls it "one of the damnedest science fiction movies I've ever seen, a berserk combination of space opera, intelligent bombs, and beach balls from other worlds." Variety says it "warrants attention only for some remarkably believable special effects achieved with very little money."