My first exposure to this song was on the The Smothers Brothers Comedy Hour back in college. Mason Williams was the head writer for the show and obviously quite a guitarist.

Here's the YouTube tape of the original preview performance with the infamous "3000 Years of Art in 3 Minutes." In the psychedelic 60's, the visuals were enough to make it a hit.

It was replayed numerous times, with my group of viewers trying to identify the art and artists flying across the screen like some type of insane Tachistoscope.

Reeves

Classical Gas was created using 2 Acoustic Grand Pianos, 1 Bright Acoustic Piano, 1 Electric Grand Piano, 1 Hammond Organ, 1 String Ensemble 1 (Consisting of 2 Violins, 1 Viola, and 1 Cello), 1 Double Bass Drum, 1 Acoustic Snare Drum, 1 Side Stick/Rimshot, 1 High Floor Tom, 1 Low Tom, 1 Low‑Mid Tom, 1 Hi‑Mid Tom, 1 High Tom, 1 Closed Hi‑Hat Cymbals, 1 Crash Cymbal 1, and 1 Chinese Cymbal.