Well!!
Of course you can dress up like Dean/Cas/Sam!
And the music of the party would be AC/DC, Eye Of The Tiger, the Weight(by Jensen Ackles!!) etc ;).
And for the games!!!
A Supernatural Sober Drinking Game!
Instead of booze, you use chocolate or cake ;).
And a game that lasts the whole party!
Remember the season 3 finale when Lilith was hiding in Ruby? Well, a random guest gets a sign of you that he/she is Lilith! Throughout the party, ALL the lights will be turned off for a minute and Lilith will tap people's shoulders. As a person's shoulder is tapped, he/she will be possessed.
At the end of the party, the people who are not posessed can guess who Lilith is! =)
And maybe before the party you can try to invite Misha Collins over via twitter! And at the party you show your twitter and hope he retweets you! :).
WRITE SCENES ON PAPER THEN DROP THEM IN A HAT &THEY HAVE TO ACT OUT THE SCENES THEY DRAW WHILE THE OTHERS TELL WHOS SCENES THEY ARE OR WHAT EPIS FROM OR WHATEVER,!PIN PICS AND HAVE PIN THE TIE OR WHATEVER ON DEAN &SAM ,!HAVE SUPERNATURAL GOODIES COOKIES BROWNIES CAKE EX...DRESS AS UR FAV CHARACTER OF SUPERNATRAL!!!!
For food you can have a cake with the face of Dean, Sam, and Cas or an impala cake.And maybe pies, burgers, and chocolate.
For the games you could watch clips of SPN on youtube or you can make one for everyone to watch, play SPN trevia game, Quiji board. OR! (this is my favorite) set up a homemade cardbord maze for people to crawl in and while they're in there you can scare them with some of the scary characters from SPN. But make sure its strong enough so it would't break, dont put nails or any sharp things in there bcoz it might be dark, make it big enough for at least two people to fit in bocz people tend to turn around sometimes. You can also put hidden prizes inside the maze for peple to find.
i had one of those we all dressed up as characters from supernatural and not just dean or sam some of the deamons and other bad guys even bobby someone even came as the scarecrow from season 1 we played trivia games we had supernatural related food one of my friends mums made a cake of deans car it was fantastic we watched episodes of supernatural and all the music was from supernatural at first my friends thoght it was going to be lame but they ended up having a fantastic time it was loads of fun and we had a blast