The "hit in Germany during the fall of the Berlin wall" is a quip on David Hasselhof who had a hit in Germany during the fall of the Berlin wall with "I've been looking for freedom".
The name of the episode is a reference to a famous quote from Casablanca. When Elsa and Rick say goodbye at the Airport he says "Here's looking at you, kid."
Charles' song being sampled by several rappers is a reference to David McCallum, whose Jazz records were sampled by many artists, including DJ Shadow, DJ Jazzy Jeff, Kendrick Lamar or Dr. Dre.