Calvin was trying to figure out what a MacGuffin is and is the ring in Lord of the Rings a MacGuffin. It turns out that his definition wasn't quite right, its a term from Alfred Hitchcock that refers to something that gets you into the plot but actually has nothing to do with the real story.
MacGuffin - Wikipedia, the free encyclopedia

A MacGuffin (sometimes McGuffin or Maguffin) is a plot device that motivates the characters and advances the story, but has little other relevance to the story