Tonight's the night

John just graduated from clinical psychology and opens his first office. After some successful advertising he is astounded to have nearly 300 people wanting to be in group therapy. John decides to rent a big hall and invite the entire group. To break the ice, and to get the therapy started, John decides to ask a show of hands how often the attendees had sex. He first asks for a show of hands of all the people who had sex almost every night. A modest number of hands were raised. He then asks, how many had sex once a week? This time a larger number of hands were raised. John then asks how many had sex once or twice a month? Again a few hands were raised. After John polled his group several more times he noticed one guy sitting off to the side with this huge beaming grin on his face. John noticed that the guy never raised his hand, so he asked him how often he had sex. The guy said, “Once a year!” To John's dismay, he responds, “Why are you so happy getting sex only once a year?” The grinning guy responds, "Tonight’s the night!"