Until tonight.
After sitting in the hot tub for all of five minutes, the boys decided that they would jump in to the pool which was frigid cold, and swim one full lap. Charlie led the charge, followed by his two thrill-seeking sons. Here's Henry paddling and kicking as fast as his little limbs can manage:

Meanwhile, the girls stayed in the 103 degree hot tub because while we love a challenge, we're not totally crazy. And given the option of being miserable and cold ... or happy and warm, we unanimously opted for the latter. Must be something about the XX chromosome.