I've seen similar things be done before. But to see it live, on Norwegian TV O_o
This was done live on the program "The Big Choir Battle" (Det Store KorSlaget)
The choir by Erik og Kriss did Super Mario, all a cappella (no instruments allowed)
Notice how they even did the points on the digital overlay, all live.
The Mario costume looks very official =P
They didn't get voted out of the contest ;)
If they had, with this song, I would have been mighty disappointed of my fellow people O_o