This is an old one from back when I first started reading Supernatural fic, so it may be gone now. It's fairly short, gen or crack/comedy.

The only thing I remember is Mike Holmes from Holmes on Homes and Mike Makes It Right comes to a house Sam and Dean are at because of a hunt. Mike goes through the house like he does in his show and finds numerous things that need to be fixed, both mundane and to keep out things like ghosts and other supernatural creatures.