While visiting our friends in Glenwood Hot Springs Colorado we took advantage of the hot water pools that are located in the heart of downtown. Its really a tremendous way to spend several hours. There were two main pools open - one about 104° and the other cooler with varying temperatures depending on where you were (along the edges were definitely cooler). The pools where enormous - the longest one felt like the length of 3-Olympic pools (no kidding). There were some water slides which looked like a lot of fun but they are closed in the winter (not sure why - I can't image soaking in the pool when its 80° outside!).
There is a hotel right on the premise and that would be an excellent way to really enjoy the pools giving you the opportunity to come and go throughout the day. There's a bunch of different restaurants within walking distance and the amtrak station is right next door. Next time you're in the area we highly recommend it!