You will never be happier to get a 404 error than if you land on this one from a Russian construction company whose web engineers clearly have a sense of humour.
The stick figure dancing is delightful, and the dude bobbing his head along is the icing on the cake. Add it to your best 404 pages list. And you can turn the music off, but you shouldn't because it gets even better towards the end of the song. Dosvedanya everybody!