We call this one, "Conversation with Zach"†:
Zach: "What's the difference between set up and setup?" (Make appropriate hand gestures to delineate the two) "Like with a space and without a space, what's the difference?"
Brother: "With a space, it's a verb. Without a space, it's a noun."
Z: "Oh, boy."
B: "OK, if you're going over to Dad's house to check out his computer setup, that's no space. The setup is a thing, a noun. If you are going over to set up your Dad's computer, there's a space. You're doing something, it's a verb."
Z: "OK, so if I say the JOA‡ is set up in Quorum,§ that has a space?"
Z: "What if the JOA is not set up in Quorum?"
†FOOTNOTE (crossed): Zach is sort of like Brother's Hans. Though Hans is mostly *intentionally* funny.
‡FOOTNOTE (double-crossed): Joint Operating Agreement, my bread and butter.
§FOOTNOTE (swerved): A petroleum industry-specific database program.