Laughter Yoga is a great stress reliever--and you don't even need to hear anything funny for it to work.

Laughter Yoga is an intentional exercise involving movement and breathing to promote voluntary laughter. Laughter can be faked, and the human body and mind don't know it's faked.

When done in a group, the contagious element of laughter quickly spreads to other people nearby, and the group gets the benefit of breathing in fresh air, expelling stale air, and our brains release endorphins--all of which make us feel better and less stressed.