Do you a.) live reasonably close to downtown and b.) not have a pool of your own?
Well, welcome to my miserable life.
But the scorching heat of a Las Vegas summer can be alleviated with a trip down to the Muni pool. It's huge, with lots of roped off lanes if you want to do laps and be separate from the scads of kiddies splashing around the main (shallow) area. And they also have a couple of hours in the afternoons of adults only swim time. (Remember how you hated that as a kid? Well, it's pretty frickin' great now!)
Lifeguards are pleasant and keep the rowdies under control. None of this is an issue in the non-summer months. There are hardly any kids to be spotted when school is in session, and it's temperature controlled for year round swimming. Just you and a few other old farts paddling happily around. It's only $1.50, but if you join in Feb., they have a family special- up to 8 people for $160 for the whole year. Can't beat that with a stick, especially since it includes use of their little gym which I avoid like the plague.