Here is a very interesting New York Times article about a group that is reusing dumpsters in New York City and turning them into pools. Sure it sounds gross at first blush, but this has got to be recycling at its most innovative. The dumpsters are cleaned, sealed with a plastic liner, and even have a filtration system - turning them into an "urban country club."
This reminds me of my own, extremely country club from my youth. When my cousins and I would visit my grandparents on their farm during the summer, my grandpa would roll out one of the huge, round, metal troughs once used to water cows. He would fill the rusting, retired container with icy water from the garden hose, we would don our swimming suits, and hop in. It wasn't fancy, and it probably wasn't so sanitary, but it was fun.
Uhm, yeah. Essentially one of these.
Sloshing about in those makeshift pools with my cousin Megnut is one of my favorite childhood summertime memories. I wish life was still that carefree, when all it took to be happy was a water trough and a garden hose.
Go forth and be innovative. But avoid E. coli...keep your mouth closed.