The fire escape stairs where JD and Turk are singing from are the exact same stairs where Joey and Ross (FRIENDS) are trapped in when they were looking for the Bapstein-King Comet.
Even though not credited and has no lines, Snoop Dogg Intern is seen for a split second during rounds standing next to Murphy.
The surgical vs medical intern face-off and Turk and JD singing on the fire escape is a reference to the Sharks vs Jets from West Side Story.
First appearance of games that Turk and J.D. play: The First One to Throw the Hat on Rowdy, Steak, and Ankles.