Glen Campbell - Guess I'm Dumb (Capitol 5441; 1965)
Although it isn't the rarity it used to be thanks to its appearance on a handful of compilations, Guess I'm Dumb remains an interesting glimpse into what might have been if the connection between Glen Campbell and the Beach Boys had remained intact a little bit longer. Of course Campbell wouldn't have had the career that he did--Guess I'm Dumb was a flop, and it's not too hard to see why--but this Brian Wilson production remains a gorgeous artifact of the musican/songwriter/studio whiz wunderkind at the height of his powers, still hanging on to his ego and faith in the belief that pop music could aspire to greater things.
As an added bonus, here's Campbell performing Guess I'm Dumb on Shindig, two years before he started hitting his stride chart-wise with Gentle on My Mind and By the Time I Get to Phoenix. Can you imagine a major label today letting an act go hitless for so long?