Last week I started doing Bikram Yoga. It's one of the most strenuous, amazing things I have ever tried - spending over 90 minutes in a 105 degree heated room pushing my body into positions I didn't even know were physically possible.
Since starting to do it every other day, I've felt the healthiest I've ever felt in my entire life. It's mindblowing what this stuff can do for your body. I've started sleeping better, waking up with more energy, and just generally feeling absolutely amazing, in addition to being better protected against Carpel Tunnel and who knows what else the future might otherwise hold.
Anyhow, I strongly suggest trying it out. It's rather difficult and even frustrating the first few times, but after 3-4 sessions you won't remember how you lived without it.
If you're in Seattle, I'd recommend The SweatBox. They have a 1 week unlimited trial for $15. No sweat, right?