Over at 43 Folders, Merlin Mann mentioned the "Sullivan nod," which, according to Wikipedia, is a "sales technique used to create a subconscious suggestion to a customer to purchase one particular item out of a list of like items."
A Sullivan nod is executed by nodding slightly, by approximately 10–15 degrees, when the item it is hoped the customer will choose is reached. The key is to make the nod perceptible, yet subtle, so as to not distract. The nod is best done with lists less than 5 items in length. Studies have concluded that 60–70% of the time, a Sullivan nod will result in the customer choosing the 'recommended' item.
The Sullivan nod has been used for years, but I just heard about it. Consultant Jim Sullivan, the creator of this technique, claims it "even works over the phone for room service orders."