Today’s xkcd is especially clever and humorous. The main character becomes aggravated whilst arguing with someone on tech support and asks to be forwarded to someone who can actually help. The engineer helps him with his problem almost immediately and states that he can use a password, Shibboleet, whenever he needs help in the future. Shibboleet is a portmanteau of Shibboleth and Leet. The word shibboleth “originates from the Hebrew word ‘shibbóleth’ (שִׁבֹּלֶת), which literally means the part of a plant containing grains. It derives from an account in [Judges], in which pronunciation of this word was used to distinguish Ephraimites, whose dialect lacked a [“sh” sound], from Gileadites whose dialect did include such a sound.” It was also a subject of an episode of The West Wing.
The author of xkcd has been known in the past to create similar word plays in order to make a joke. My personal favorite is Malamanteau, which is simultaneously a portmanteau and a Malapropism. It was created to make fun of Wikipedia.