Floating through crystal-clear water to refresh your margarita at a swim-up bar is no longer limited to private islands and luxury resorts. The concept of the swim-up pool bar started in — where else?

I'm writing from the deep end of summer swim season. We're at the aquatic center. The Clarksville Sea Dragons, Paris Piranhas, Alma Gators and Fort Smith Tideriders are already in the pool. My two ...