6. David Bowie and Bing Crosby - 'Peace On Earth/Little Drummer Boy'
One month before Bing Crosby died, he cut this wonderfully bizarre duet with David Bowie for his TV special Bing Crosby's Merrie Old Christmas. Bowie supposedly hated "Little Drummer Boy," but was willing to do it for the chance to work with Crosby, who his mother loved. Last year, Will Ferrell and John C. Reilly recorded a hysterical shot-for-shot remake of the duet where they stuck exactly to the dialogue from the original.