The drawing of the Hellhounds in the book is 'Cerberus' by Todd Lockwood, who is famous for his art in Dungeons and Dragons books, and Magic the Gathering cards.
In this episode, Sam tells Dean he totally should've been "jammin'" his good-bye speech to "Eye of the Tiger"...and Dean does eventually jam to that very song in the Season 4 episode Yellow Fever (2008).
Ruby compares a futile knife attack against Lilith to " hitting Hitler with that exploding briefcase". On 20 July 1944, at a top level Nazi military conference a briefcase containing 2.2 pounds of plastic explosives was placed near Hitler's seat. However a sturdy table leg between Hitler and the bomb shielded him from the blast. The meeting was to take place in the Wolf's Lair, a concrete bunker with a steel door and no windows, but was moved to a wooden bunker above ground. 2 bombs were set to be used but only 1 was able to be armed. Had the meeting taken place in the concrete bunker the shrapnel would have killed everyone near the bomb, including Hitler.
Lilith is in the Jewish Apocrypha. According to the stories, Lilith was Adam's first wife (first story of creation in Genesis) who was created alongside Adam. She refused to obey Adam and was cast out of the Garden. In some ways, Lilith is the first demon (a human who goes to Hell.) Up to this point all of Hell's other inhabitants are fallen angels.
When Dean sarcastically says that he loves their plan "I'm excited to be a part of it" he's paraphrasing a line of Peter Venkman in Ghostbusters (1984).