Random ideas that I got by reading fic and may never write:
1. (inspired by embroiderama
) Jared is all fucked up after breaking up with Sandy and Jeff ends up being his father confessor booty call one night and so they end up having this one night thing (or possibly a friends with benefits situation). In the meantime, Jeff has been pining/lusting after Jensen all this time and has done nothing about it. And Jensen finds out about Jeff shagging Jared and he's all put out because HE'S been lusting/pining after Jeff all this time except now he figures Jeff is "taken" because Jared got there first and there's boys being stupid and pissy and jealous and trying desperately to pretend they're none of those things until Jared's like "DUDES. You're stupid for each other! GET OVER IT AND FUCK ALREADY." And then there's happy buttsexing. Possibly with a side of Jared/Chad, wtf?
2. (inspired by tabbyshh
) This one could become original fic REALLY easy. Jeff is a wealthy successful businessman and Jensen is his kept boy-toy. They've been together since Jensen was fairly young and Jeff is Jensen's first (or practically). Jensen didn't mean to be a boytoy, but somehow his life plans kept getting postponed or pushed aside (mostly by him, himself) in the interests of staying with Jeff and not making things difficult and being available whenever Jeff might want him around. But now it's been 12 years and Jensen's self esteem is crrap and his whole self-identity is hinged on his relationship with Jeff and he realizes he really needs to get himself together and have his own life. But he doesn't want to leave Jeff and so he struggles to both find himself and keep his relationship together.
3. (inspired by no one in particular) If the Jared/Chad doesn't end up going in that first fic, I could end up writing that all by itself. Again, WTF? No actual plot to speak of, just one scene in my head about Jared trying to come out to Chad while playing old school Mario Kart and Chad not being a total asshole about it.