I have a soft spot for kidfic and fic with main characters in happy domestic situations. However, I've never warmed up to mpreg. Most of what I have read over several fandoms is silly, not make you smile silly, just plain old "this makes no sense" silly. For that reason I was shocked at how much I liked both "Babbydaddy" (featuring a shocked knocked up Dean, Sam, and babbydaddy Castiel) and its sequel "Best of All" (featuring said baby as a three year old, with Uncle Sam and Aunt Ruby babysitting) by pandarus. http://pandarus.livejournal.com/264348.
These two fics made me laugh out loud. They are written entirely as unattributed dialog, but the voices are so in character that there is no problem figuring out who is speaking. There are allusions to sex but nothing graphic. The best part is that this author has her tongue firmly planted in her cheek in same way as Hitch Hiker's Guide to the Galaxy or Pushing Daisies.
Here is snippet where Sam has been reading Where the Wild Things Are and his nephew critiques Ruby on her participation.
“Okay. Where were we? Right. Ahem... And he came to the place where the wild things are. They roared their terrible roars.”
“ROAR! Aun' Wooby, you have to roar.”
“Oh! Okay, sorry, kid. I'm kinda new to this. ROAR! That okay?”
“Yes. That was a very good roar.”
“Cool. Go me.”