When I first heard about napkin pitches some years back, I was intrigued. The concept is that if you cannot sell your business model to a venture capitalist within the space of a napkin over dinner, you had better re-think your business idea. It was all about capturing the essence, the succinct crux of the business, within that short window, much like an elevator pitch. Since then, I've prepared "Napkins" for topics whilst studying in university; the succinct salient points that I need to know for each chapter.
Here is a NYTimes site that pays homage to this concept as well: capturing snapshots of financial advise on napkins. Enjoy: http://www.nytimes.com/interactive/your-money/carl-richards-gallery.html?ref=your-money.
Better yet, how about a book dedicated to napkins and visual thinking? :)
Uncle T