Doofus by why_me_why_not -- (Sam/Dean, R, 1,400 words) -- Sam gets jealous and Dean reminds him of how things are. The thing Dean says about Sam and the Impala is POSSIBLY one of my favorite scenes in any fanfic, ever.
Every Little Thing You Do by fiddleyoumust -- (Sam/Dean, NC-17, 6,700 words) -- Sam falls hopelessly in love with Dean and it takes Dean just a bit to catch up. This story is beautifully written and reads just exactly right.
Just a Taste by mickeym -- (Sam/Dean, NC-17, 2,480 words) -- Sam is hungry, he wants to taste Dean...so he does. This is so hot and sexy, it made me flush red hot, all over.
Stories for Sixteenth Birthdays by albydarned -- (Sam/Dean, NC-17, 20,000 words) -- Dean gives Sam a very special present for Sam's sixteenth birthday. This is truly one of the best fics I have read in a long time. The characterizations are great, the way the story progresses is amazing and whoa...SMOKING hot sex. And all of THAT? Tied up in love and emotion and care.