Swimming pools — so awesome and fun, but so not actually good for the environment in any way. But KB Custom Pools, a pool company in Texas, has a sorta-kinda-more-like-a-real-body-of-water alternative. Their Eco-Smart pools match the topography of your backyard, use a filtration system that doesn't require harsh chemicals, and can be heated using solar panels. Gizmodo goes so far as to say it's positively lake-like (minus, of course, the mucky bottom and the fish).
Of course, if, like this company, you're located in central Texas, there's still the itsy, bitsy problem of record-breaking droughts, which means that there's still probably better uses for that water. But with 100 days over 100 degrees, we understand why a pool is appealing.