You'll make your real friends,
Those cunning folks use any means
To achieve their ends"
Slytherin was founded by Salazar Slytherin, who came from a fen (whatever that is)and had a feud going with Gryffindor over wheter or not muggle-born wizards and witches should be allowed into Hogwarts. Gryffindor won the fight, much to the dismay of Slytherin. In revenge Slytherin built the Chamber of Secrets, which could only be opened by his heirs. Once it was opened, a large basilisk would kill all the muggle-borns in Hogwarts.
Slytherin is represented by the snake, and the house colors are silver and green. The house ghost is The Bloody Baron and the head of house is Severus Snape. The quidditch robes its team sports are green with silver lining. Their common room is hidden behind a wide stretch of wall in the dungeons, and you can tell the password to the wall, which will slide open and let you in.
No house has ever turned out as many dark wizards and witches as Slytherin.
Famous Slytherins include: Voldemort, Severus Snape, Draco and Lucius Malfoy, and pretty much all the Death Eaters.
The Western Tower