Charlie:
(to Hank) This is cool, us hanging out here, right? It's like, uh, like, uh, Raoul Duke and Dr. Gonzo, right?
This is a reference to the the 1998 movie
Fear and Loathing in Las Vegas, which was based on a 1971 book written by Hunter S. Thompson.
Johnny Depp played the role of Duke, and
Benicio Del Toro played Gonzo. The movie is about a road trip to Las Vegas, during which the two encounter many problems as they take various drugs.