If you’re a flip flop fanatic (and why shouldn't you be), chances are you’ve got a spare pair or two that are due for retirement. Instead of donating them to your neighborhood thrift store (although that’s good too), consider dropping them off at your local Old Navy outlet. From now until May 21, the nationwide retailer is teaming up with trash-to-treasure eco-company TerraCycle to collect old flip flops and turn them into four public playgrounds in communities across the U.S. How cool is that?