This Bulgarian folk song, Izlel e Delio Haidutin, sang by Valya Balkanska, was shot into space on Voyager 1 and Voyager 2 in 1977. It's quite fitting it was shot into deep space as it REALLY gets out there, man!! I'd reckon it's...slightly-delic?!
The Carl Sagan-chaired committee complied the contents of the Voyager Golden Record, it's musical contents is mostly classical, save this folk song and of course, Chuck Berry's "Johnny B. Goode." With such a swath of earthly sounds, I can only imagine what an alien's reaction might be.
At current speed, and on it's current trajectory, Voyager 1 should pass the closest star in about 40,000 years.