Hooker by Crook: A Strange Context Joke

We also got a bunch of emails about the episode by Hooker by Crook as we missed a very strange continuity joke. Will is talking to his attractive tutor, dealing with the idea that she is telling him to cheat. Behind him is a sign that says sex ed. Then in another take, a comma has been added between the words sex and ed. And a question mark is placed after it. We must have had a background actor grab a pen. That's one of the best things I've ever seen. It cuts back and the additions are gone. So it looks like someone is asking Ed a question. What a cool one. They'll keep me. Well, special thank you