Laughter Yoga (Hasya Yoga) is a physically oriented technique that uses a blend of playful, empowering and otherwise "tension-releasing" simple laughter exercises. With gentle yoga-breathing and -stretching exercises, rhythmic clapping and chanting of Ho Ho Ha Ha Ha in unison a simulated laughter turns into real laughter. Laughter Yoga is done as a way to improve health, increase well-being and promote peace in the world through personal transformation. It is non-religious, non-sectarian, and non-political.
A typical Laughter Yoga session lasts about 20 to 30 minutes. The session may be adapted to suit the needs, abilities and motivations of the group participating.
The Laughter Yoga method is the brainchild of Dr. Madan Kataria, a family physician from Mumbai, India who started the first laughter club in 1995. He has been the catalyst for the creation of over 5,000 Laughter Clubs in 40 countries, mostly free and public. [Laughter Medicine : Corporate Stress Management Training & Laughter Therapy Laughter Yoga International], 2007, Laughter Medicine : Corporate Stress Management Training & Laughter Therapy

You can find videos here: http://www.youtube.com/laughteryoga

Lama, you can do it yourself or your partner, friends, children (probably even better).
Just enjoy!