Tropical Smoothie Café is hosting it’s National Flip Flop Day on Friday, June 16th! All customers wearing flip flops will receive a FREE Sunshine Smoothie in their  NEW limited edition 16 oz. 20th anniversary souvenir cup. The annual giveaway runs from 2 to 7 p.m. today at the Atlanta-based chain's nearly 600 locations.

Mike Rotondo, CEO of Tropical Smoothie Café said that it had been over 10 years since they started National Flip Flop Day to show appreciation for their guests and mark the kick off to summer.

National Flip Flop Day® is Tropical Smoothie Cafe’s own holiday when they celebrate their customers and kick-off fundraising for Camp Sunshine of Casco, Maine. The event is held each year on the third Friday in June.

Camp Sunshine offers countless families the opportunity to put aside the stress and severity of having a child with an illness and just have fun. It costs $2,500 to send one family to camp for a week, but through donations many are sent.

Tropical Smoothie efforts make a real difference in the lives of the children and families that attend Camp Sunshine. This year, over 4 Million dollars has been raised toward that effort.

The special smoothie — a combination of orange, orange juice, banana, pineapple and mango was created for the 11th annual event and only will be available today, June 16. No coupon or purchase is needed to get the free smoothie.