1. Supernatural was originally going to be called Unnatural.
2. Jared Padalecki and Jensen Ackles were voted People Magazine's "Sexiest Ghostbusters" in 2005.
3. Jensen Ackles planned to study Sports Medicine and become a physical therapist before moving to LA to become an actor.
4. Dean has killed the most main antagonists on the show.
5. Padalecki's dogs Harley and Sadie share his trailer with him on set. They also starred with Ackles in PETA's "If you wouldn't wear your dog..." campaign.
6. The license plate on the Impala is KAZ2Y5, which is a subtle reference to the Winchester's home state Kansas and the year 2005 when the Supernatural premiered.
7. The brothers come from the bloodline of Cain and Abel, according to Archangel Michael in the episode "The Song Remains the Same."
8. Dean has entered the most number of realms, including Heaven, Hell, Purgatory, and Avalon (The homeland of the fairies)
9. Jensen Ackles starred in a TV Movie called Blonde, where his best friend's name was Cass.
10. Jim Beaver’s character (Bobby) was only supposed to make a one-time appearance.
11. Dean Winchester is allergic to cats.
12. The Latin inscription on the barrel of the Colt says ‘non timebo mala’, which translates into 'I will fear no evil.'
13. Sam always wins at Rock, Paper, Scissors against his brother; Dean always chooses Scissors.
14.The original concept for the show had a reporter going to investigate the urban legends and writing about them in his column, and had absolutely nothing to do with the Winchester Brothers.
15. The deleted scene of Dean lip syncing "Eye of the Tiger" was ad libbed by Jensen Ackles. The crew had decided to play a joke and stop Jared Padalecki from hitting his queue to interrupt Jensen's initial (and scripted) scene.
For a short period, you could call Dean's phone. If you called 866-907-3235, you'd hear Jensen Ackles reading the message "This is Dean Winchester, if this is an emergency, please leave a message. If you are calling about 11-2-83, page me with your coordinates.'' 11/2/83 is the date of Mary Winchester's death.
They have changed the number and message since then. If you call 866-907-3235 now, you will hear "Dad? We really need to hear from you. Leave me a message, text me, check your jwinchester1246 email(a working email address). Anything. We have new info. "
The number no longer works.
17. The only known sources of income for the Winchesters are credit card scams, poker games and playing pool.
18.According to set director George Nevman, the set for Bobby's place had around 5000-6000 books "All over the place in stacks, waist-high in books, the entire set. Up the stairs, even, everywhere you looked there were stacks of books, books, books."
19. Season 1 had a budget of just $20,000. This includes actor wages and the special effects budget.
20. The series has also developed an expanded universe. Three six-issue comic book mini-series have been published depicting the early lives of John, Sam, and Dean Winchester.