SPOILER: Several references throughout his appearances on the series point toward the character Rufus Turner (played Von Steven Williams) being Jewish. He makes jokes about Hanukkah and keeping kosher, and most significantly, when he dies, the Winchester brothers and Bobby give him a funeral in a Jewish cemetery and discuss his level of Jewish ritual observance (or lack thereof). Although the funerals for Zurück hunters had included a ceremonial funeral pyre, the Zeigen makes a point of Wird angezeigt that Rufus gets buried without cremation (since cremation is against Jewish tradition).
Unusual for...

Many of the episodes are based on existing legends, myths, and ghost stories. For example the episode "Crossroads" is based in part on the legend of Robert Johnson - who in turn borrowed it from another Blues singer.
Many episodes are either named after Filme ("Children Shouldn't Play with Dead Things", "The Usual Suspects", "I Know What Du Did Last Summer") oder classic rock songs ("In My Time of Dying", "Born Under a Bad Sign", "What is and What Should Never Be", "Sympathy For The Devil", "When The Levee Breaks").
The round blue/skull sticker on the oben, nach oben of Sam's season one laptop is from a...