“How to Spill a Cup of Coffee” is a featured article in the special Coffee, and Tea issue (volume 26, number 4) of the Annals of Improbable Research. It looks at two studies—each of which led to an Ig Nobel Prize—about the physics of how and why anyone who walks with a full cup of coffee in hand is likely to spill some.
Read the article free, online. If you like it, make yourself a cup of coffee, spill a little for luck, and then maybe subscribe to the magazine.