DUDE! I was just coming on to post about that. That episode totally made my day.
That's one of my favorite shows, and it just got even better with those references.
EDIT: Actually, after thinking about this last night, and I had never thought of this… but hearing that theme music with those guys on screen at the end… I really think that they could potentially do something really good if they were ever in something officially Ghostbusters related. Particularly the guys who play Mac (Rob McElhenney) and Dennis (Glenn Howerton), Charlie Day would be good too, I think, if toned down from his character level as Charlie Kelly. It was so great seeing that theme playing at the end of an episode though, even if it wasn't an actual Ghostbusters TV series.