A noted sex therapist realized that people often lie about the frequency of their sexual encounters, so he devised a test to tell for certain how often someone has sex. To prove his theory, he filled up an auditorium with people and went down the line asking each person to smile. Using the size of the person's smile, the therapist was able to accurately guess how frequently they had sex. That was until he came to the last man in line... this guy was grinning from ear to ear. "Twice a day." guessed the therapist. "No." said the man. "Oh, then how about once a day?". Again, grinning like a cheshire cat said "No." ..."Twice a week?"..."No"..."Twice a month?"..."No"..."Every second month?"..."No"..."Okay, then. How often DO you have sex?" The man replied, "Once a year." The therapist was a bit confused. "Then why in the heck are you smiling?"... The man said," 'Cuz tonight's the night!"