I had a similar three sided album by Keith Jarrett. Unfortunately it was lost subsequent to a break up with an old girlfriend. Also lost was my original copy of The Beatles with Tony Sheridan on Savage Records AND my Paul McCartney Intervew Album. A painful memory....

Lest we forget "Second Winter" by Johnny Winter with the blank 4th side. Remember Columbia's ill-fated $.99 one sided singles?

"It's a Gas", a cardboard-pressed record that came free in copies of Mad Magazine (1965?), had double grooves, although I think it was only at the end of the "song" (a stock sixties instrumental with belches every once in a while) and didn't really work, if I recall correctly -- once the needle had gotten used to going with one of the two grooves, it wanted to go to it every time.