Flip Flop Day is a holiday that celebrates the casual beach shoe worn by people in tropical areas all year round. For most people around the world, though, flip-flops are exclusively summer shoes, so what better time to celebrate them than the middle of June? This holiday was started by Tropical Smoothies Cafe as way to raise money for charity and give people an excuse to wear flip-flops around town. On this day they give free smoothies to anyone who comes to the cafe wearing flip-flops. It is celebrated on the third Friday in June.