Former studies showed that a cartoon, such as a smiling face or a cheerful drawing (i.e., the image of the sun), increased the amount of tips given by a customer when added on a bill. A replication was made in accompanying the bill with a small card on which a joke was appended. The experiment took place in a bar with people who had had the same drink. The results showed that people who received the joke card were more likely to tip than were people in the control condition or in a condition where an advertisement card accompanied the bill. The size of the tips left tended to be higher in the joke-card group than in the other conditions. The findings are discussed in terms of the positive mood activated by the joke card, which in turn increased tipping behavior.