Do you have any songs that just don't fit with the rest of your library? Do you specifically love these songs? Or is this an entire album that's outside of your normal tastes that you just like?
For me, I have the Spongebob Movie soundtrack, because Spongebob And Patrick Confront the Psychic Wall of Energy and Ocean Man are awesome songs, by the Flaming Lips and Ween, respectively.
This is my favourite song to show people. It makes you look worldly without even trying. Also, the amount of control they have over their voices is amazing.
My whole library is out of place, I have nearly all genres in there.. so can't pick one, maybe 'Big fish little fish cardboard box' by Bob the Builder, is the oddest one.