Hey, I'm looking for Sam and Castiel friendship fic. No slash, just Sam and Castiel becoming/being friends, or working together without antagonism. Dean, of course, is welcome. I'd love to see a case fic the three of them work on, when Sam and Castiel aren't at each other's throats.

So, what are your favorite Sam and Castiel friendship stories? Long, short, funny, sad, silly, serious, whatever.