Simon unmemorably described it as "this version that was on the Internet by Israel somebody," but if you're wondering where American Idol's Jason Castro got the idea for his ukulele-assisted cover of "Somewhere Over the Rainbow," it was originally performed by Hawaiian singer Israel Kamakawiwo'ole, better known as Bruddah IZ. (Castro gave IZ a shout-out in his introduction.)

Thanks in part to appearances on TV commercials, in movies, and in Mark Greene's death scene on ER, the medley of "Somewhere Over the Rainbow" and "What a Wonderful World" became a world music hit after Kamakawiwo'ole's 1997 death from complications of morbid obesity. The album it appeared on, Facing Future, is the subject of a forthcoming book in the 33 1/3 series by — full disclosure — some moron who's way behind schedule.

Castro's version was pretty loyal to Bruddah IZ's — a little bit bluesier, with a little wash of strings in the background that IZ didn't have until ten years after he died, when his canny record company recorded orchestral versions of his songs. It was by far the smartest song choice of the night, we thought, and the performance was really nice, even if Castro weighs one-eighth what Bruddah IZ did.