Is there a book in it?

I was reading a literary agency website, and found this:

There's a cartoon that shows two women nursing cocktails and one is saying to the other: "I'm marrying Marvin. I think there's a book in it."

Which got me thinking if that's a good question for writers to apply to all the things we do. Is there a book in it? Or maybe there's a book in everything? I remember one of my writing students who was a great writer, beautiful voice, good storyteller, but she was convinced there was nothing interesting about her life. And there are others, not in my class, but I've heard, who are convinced everything they do is fascinating. Somewhere in the middle is the book. A good deal of what we do can be told in a way that makes it fascinating to a reader, but there's a lot to be said for adventure, too. Btw, who's Marvin?