From this interview (along with "Thor") I learned that Natalie Portman had done a rap song. And not just any rap song, but as filthy as anything the big black dudes have done.
You can get an uncensored version, but I sort of think the bleeped version is funnier, you fill in the blanks yourself.
... And she really is this small, sweet, highly educated person. I guess the real talents keep surprising you.