Atari's Groove Tube

Smack dab between the release of home PONG in 1975 and the VCS in 1977 came the Atari Video Music in 1976.  The brainchild of home PONG creator Bob Brown, you would plug your stereo via RCA jacks into this piece of ordinance, and output to your TV via a RF connector.  Thusly, the Atari Video Music would display trippy graphical patterns on your TV, in time to your music.  The box is hard-wired analog, with nary a processor in sight.  Think of it as an early version of today's mp3 player visualizers.  You can grok the effect in this YouTube video:

Read more about the device here at Technabob.  What would your choice of "mind-enhancer" be when watching this thing?