Look up "Leningrad Cowboys" on some anonymous video-hosting site that I'm not going to mention by name because it's banned. They're a Finnish cover-band that's covered Dschinghis Khan, Lou Reed, Bob Dylan, the Beatles, etc.

Guess who does their backup vocals, though...?

THE RUSSIAN RED ARMY CHOIR.

In particular, look for their covers of "Stairway to Heaven," "Delilah," "Knocking On Heaven's Door," "Yellow Submarine," and "Happy Together."