Add one of our running gags— it's the Agaric way, after all

content-style-guide.md

@@ -112,6 +112,12 @@ Agaric’s tone is usually informal, but it’s always more important to be clea
 
 Agaric has a sense of humor, so feel free to be funny when it’s appropriate and when it comes naturally to you. If in any doubt, don't make the joke. Generally avoid humor in written communication to clients.
 
+#### Running gags
+
+##### "The Agaric way"
+
+We've been saying it from the beginning and are only half-serious about it.
+
 ### Style tips
 
 Here are a few key elements of writing Agaric’s voice. For more, see the Grammar and mechanics section.