Hey, don't know the fic you're looking for, but Staring In (http://callistosh65.livejournal.com/130459.html) (gen) and This Fortress Made of Us (http://mickeym.livejournal.com/1107156.html) (Sam/Dean) have Dean finding out.

They aren't the specific fic I was looking for but they definitely in the category of fics I'm looking to read. Thanks

I'm not sure of the fic but I haven't read Mystery Spot Codas for awhile so it may be one of the stories I'm going to rec to you. Who Knows? Hahaha

Never Saved (http://www.fanfiction.net/s/5344122/1/Never_Saved)
Summary: While on a hunt, Dean reads the book "Mystery Spot" the Chuck published. He soon finds himself in Sam's position, and can't find a way out. Refers to 3x11, "Mystery Spot" and 4x18, "The Monster At The End Of This Book". Spoilers up to 4x18, nothing more. (This is sort of what your looking for)

Goodbye Ruby Tuesday (http://www.fanfiction.net/s/4928808/1/Goodbye_Ruby_Tuesday)
Summary: Tag to 'Mystery Spot'. Sam needs to deal with the effect that losing his brother over...and over...again had on him, but it's hard when he won't tell Dean the full story. A hunt brings secrets, fears and failures into the open.

Wednesday (http://www.fanfiction.net/s/4903372/1/Wednesday)
Summary: Tag Scene to "Mystery Spot" Dean wakes up and it's Wednesday like he thought it would be. So why is Sam acting so weird?

One Last Tuesday (http://www.fanfiction.net/s/4145532/1/One_Last_Tuesday)
Summary: AU 3x11, Mystery Spot: What if Sam had tried to bargain with the Trickster instead, and the Trickster had told him there was a way out that Sam just had to figure out?

Heat Of The Moment (http://www.fanfiction.net/s/4357694/1/In_the_Heat_of_the_Moment)
Summary: Mystery Spot missing scenes: Sam was acting weird.

Wednesdays Child (http://www.fanfiction.net/s/4271137/1/Wednesdays_Child)
Summary: Mystery Spot/Jus in Bello tag: Sam's different, and Dean doesn't understand why.

There are some really great stories in here. Thanks for sending them my way!

Your Welcome!

Could also be I Carry the Suitcase of My Grief in Both Hands, Ma (http://withdiamonds.livejournal.com/462207.html) by withdiamonds.

The most recent tag I've read....

The Definition of Insanity by Faye Dartmouth
http://faye-dartmouth.livejournal.com/78059.html

This is exactly the type of story I was looking for. Thanks :)

This one from SciFiNutTX is a good short read. It's a twist on the "Sam-has-a-heads-up-on-the-next-six-months" theme, where Sam and Dean meet up with some gun runners that Sam ran afoul of while he was alone.
http://www.fanfiction.net/s/4135607/1/New_Sam
Intrigue, plot, and just the right amount of angst.