When Abbey, Amy and C.J. go into a separate room to drink wine, Abbey tells the wine was a '95 wine who belonged to king Baudoin of Belgium. In fact, king Baudoin was already dead two years in '95 so he could have never owned the wine.
Lord Marbury talks to Toby about a fine Islay whiskey but mispronounces it "iz-lay". A person of Marbury's breeding and education would most likely know that it's actually properly pronounced "eye-lah" if you are from the UK.
In the opening sequence, while President Bartlett is working on a cross-word puzzle, he is stumped by a clue about an organ that produces Hydrochloric Acid, or HCl. Abbey responds that it is the pancreas, while it is in fact the stomach.