WHAT IS THE MOST UNIQUE SONG THAT YOU HAVE EVER HEARD?

"tomorrow" [from "Annie"] played and sung by  Major "mule" Holley and "slam" stewart, on string basses. the unique part is that major holley was a human contrabass and could and did sing in unison with the strings of his string bass, all the way down to low E. it is a weird effect, he demonstrated it to frank sinatra and it made frank grin broadly at the novelty of it. 

Anything by the Dixie Dregs

Anything by Stimmhorn, or it' s vocalist, Christian Zehnder  https://youtu.be/-UsjZYzryVU

Every song on Van Dyke Parks' debut album Song Cycle will sound odd to most listeners, none more so than "The All Golden." You think Syd Barrett sounds unusual?!

After you listen to Song Cycle, go back and listen to Smile. You will then hear how much VDP influenced Brian Wilson musically in 1966 and 7. Smile was really a collaboration between the two, too good to be reduced to a mere Beach Boys album. Mike Love could barely deal with Brian's musical wisdom; Van Dyke's was just too much for him.

Aja by Steely Dan
Almost everything in non conventional but it melds together beautifully! Many time changes and melody changes is confusing and still so intriguing! I have it on LP Mobile Fidelity so it sounds incredible on my system!