See http://www.laughangeles.com/club-list.php for a list of laughter clubs near you.
Laughter Clubs (also occasionally known as Laugh Clubs, Laughing Clubs, Yoga Laugh Clubs) are fully independent, not-for-profit, non-political, non-religious and non competitive gatherings of people where all are welcome regardless of gender, age, physical abilities, social or economic backgrounds. They practice the Laughter Yoga method of Laughing for no reason as a form of exercise. Most are free. Some ask for a (usually very low) fee to help cover their expenses.