I was certified by Laughter Yoga Fun's Carole Holcombe in San Jose, California. It also happened to be in San Jose, California that I first took a Laughter Yoga workshop. It was led by the amazingly talented Celia Farran.
Laughter Yoga has been a huge influence on my life ever since, and I recommend it widely, and in almost any situation.
I like leading other people to explore the power of laughter to uplift and shift their mood and outlook. One of my favorite LY exercises is "Cry down. Laugh up" in which one folds over at the waist or knees, collapsing down while mock (or near-real) crying. Then one comes up laughing. It fills the heart to transform the energy in such explicitly simple ways, and I can't recommend this seriously playful practice enough.