Every object should have multiple uses.

Book used as a saw guide.

Working on a honey-do item from the task board today.  It was to cut the dinning room table into, shorten it by about 12- 20 inches.  I was working with a limited selection of tools.  I needed a short straight edge, skill-saw guide.  I had a 6 foot straight edge for the table top - but needed a small one for the table skirt. Looking around I couldn't find one until I looked at the book shelf.  So I grabbed "Agile Estimating and Planning" by Mike Cohn.  I though it was quite appropriate.

Table with two cutoff pieces.