This is easy and really damn good. Paris Hilton is monologuing to Dean. He claims not to be a fan. "I've never even seen House of Wax." Cue to Sam, looking offended. Yes, Jared was in the cast of that film, along with Ms. Hilton.
Here's another great inside joke. Look at the bad shirt Jared ended up wearing to the premiere of "House of Wax." That shirt would have gotten Sam Winchester's ass kicked. Yikes!
Honorable mention is just the whole idea of a Supernatural fan convention on the show let alone the boys attending one. Us fans ended up being total whackjobs with heart and not completely delusional. Dean's appreciative smile at the end spoke volumes. Kripke got it right.