Cougar Res. lake
Hoodoo, a local group has taken over running Cougar hotsprings in the recent years. They made a number of improvements to the trail and the hotspring pools.
There are four pools at the hot spring. The lower pools are cooler and for cleaning off before going into the hotter, more clean pools. There is also a really cool cave right at the top where all the hot water is coming from. You can climb up into the cave it is really cool. There is a strong sulfur smell, but cool water drips from the ceiling so it doesn't get too hot.
This is one of the best hotsprings in the US. It does cost $5 but it is well worth it. Here's the information they had up on the sign telling about Cougar Hotsprings.
-- photo blog post from my iPhone