Around the corner from where I live is an apartment building. In one of the windows in one of the units is an air conditioner. Typically, a window air conditioner is cantilevered outside the window, or better yet, braced with triangle-shaped brackets that allow the brickwork on the outside wall to carry its weight.
This apartment dweller chose the former method. Most people who won't spend the $3 for the braces find a brick or wood blocks, something stable to support the weight on the sill.
But this tenant knows better. He or she is using a phone book. When it was delivered last spring, he placed it under the air conditioner and it's been supporting it ever since.
Now, you'd think that a phone book would absorb lots of precipitation and humidity and deform from its original shape, causing the air conditioner to fall out of the window and crash on the sidewalk below, possibly while I'm walking by with my dog. Thus far, it hasn't happened.
It's coming up on a year now. With the decline of yellow pages advertising each year, I doubt this year's directory will quite fill the space.