The Ties That Bind by elise_509
Sam/Jo, ~23,000 words, R
http://elise-509.livejournal.com/154017.html

Hey There, Bluebird by lint138
Sam, Jo, 3,362 words, PG-13
Summary: Dean teases him endlessly about being best friends with a girl, but Sam never takes it to heart because he knows his brother doesn't get it. Pre-series AU.
http://lint138.livejournal.com/243808.html (or http://www.fanfiction.net/s/5310848/1/Hey_There_Bluebird)
And the sequel It's Educational, Kids: http://lint138.livejournal.com/249945.html (or http://www.fanfiction.net/s/5590633/1/Its_Educational_Kids)

She and Him by lint138
Sam/Jo, 4,145 words, PG-13
Summary: He puts a hand atop one of hers, makes a promise he knows he can't keep. Post No Rest for the Wicked.
http://lint138.livejournal.com/234477.html
or http://www.fanfiction.net/s/4319630/1/She_and_Him

http://brin-bailey.livejournal.com/tag/pairing:+sam/jo