The beloved British author Douglas Adams suggested that a towel was a massively useful thing. Now a Brazilian collective has created a towel that can bring strangers together and help them build a real life social network. The Toalha Social is a brilliantly simple way for people to meet and make friends. Users simply grab a towel from a rack in a park or public square, place it on the ground print face up, and allow others to join in conversation. A great idea that I hope will spread.