My housemate back in college had a nice system and a dog. He put in a new Pink Floyd album. The dog would look at one speaker, then the other speaker, then back to the first speaker - etc. It was pretty funny.
First time I heard Quad I did that too... Yep Pink Floyd, and the vocals would go around you in a circle causing you to try and follow it subconsciously. lol
Blew me away at the time. and as a musician I was already used to different tracks and playback. But on only two channels. It was still a blast for a unique commercial protocol. :)