Here’s one CD of bizarre covers:
When Pigs Fly: Songs You Thought You’d Never Hear (Flash site)
Including such covers as
“Shock The Monkey” - Don Ho
“Girls on Film” - Billy Preston
“Dirty Deeds Done Dirt Cheap” - Lesley Gore
The “Unforgettable” duet of Ani DiFranco and Jackie Chan is kind of sweet, though.