The Winchesters

There is a particular clock that shows up in almost every episode.
An important aspect of the show's musique is classic rock, most of which comes from creator Eric Kripke's own record collection, although one of his favori bands - Led Zeppelin - has always been too expensive to license.
The role of Ruby was written for Kristen Bell. But she turned it down, Katie Cassidy was cast instead.
Jim Beaver's character (Bobby) was only supposed to make a one-time appearance.
While it maybe coincidental the choice of the name Winchester for the family is interesting. There is a rather famous mansion in California...