CJ's fishbowl has an oil pipe. This is a reference to the plot about an oil tanker leaking oil.
After CJ's first unsuccessful interrogation, she asks Carol how many more of these she has. Carol replies "1,138," a reference to George Lucas' 1971 film "THX 1138" in which interrogation is a main plot element. This number also appears in all of George Lucas' other works including Star Wars.
CJ (Allison Janney)'s fishbowl decoration changes 3/4 of the way through the episode. Now it is a $100 bill. This is about the sub-plot about bailing out Mexico with money.
This episode marks the second mentioning of the "secret pumpkin." The first is made by Sam Seaborn in the very first episode and references Alger Hiss. In this episode Donna mentions it in reference to Whittaker Chambers. Chambers and Hiss were suspected Soviet spies, and Chambers hid film from Hiss in a hollowed out pumpkin.
In Mr. Willis of Ohio (1999), during the President (Martin Sheen)'s kidnapping speech, Zoey (Elisabeth Moss) pointed out that she was starting college in a month and that she was 19 years old. In this episode Charlie (Dulé Hill) states that Zoey was 17 when she applied for college and her health form required a parent's signature. She would have been 17 when she applied to college and 19 when she started attending.
It is also said in that episode that she is starting Georgetown in the spring, leaving at least a semester if not more (say, since she was still 17) in between graduating high school and starting Georgetown. She may have started at a different university, perhaps one that didn't give her the college experience she wanted. It is unlikely that she was held back enough to graduate high school in January at 19.