Denny breaks the fourth wall again in this episode. While fishing in the sewer he says "I always wanted to go out with my pride, failing that, at least my old time slot." This is likely a reference to the original Star Trek series which originally aired on Thursday's at 8:30.
The music (whistled) that closes out this episode is the theme from The Andy Griffith Show (1960). The connection being that that show opened with Andy Taylor (Griffith) and his son Opie (Ron Howard) walking toward their fishing hole.