LigerLearn has a nice video on using Ctrl+q in Emacs to insert arbitrary ASCII (or even Unicode) characters into the current buffer. The video begins with a discussion of ASCII control characters and the “caret notation” used to represent them.
The video goes on to discuss how Ctrl+q can be used to insert control and other characters into the buffer. That’s really handy when you want to insert a character like a newline (^J) that would normally perform an action.
The video is obviously aimed at n00bs but others may learn something useful too. It’s just under 9 minutes so it should be easy to fit into a coffee break.