Nicole, this was my first time canyoneering (you hike upstream on a trail along a canyon with waterfalls, then bushwhack to the river and rappel/swim/hike along until you get downstream to your start point), but I've climbed, rappelled, and gone backpacking many times before.
If you or your husbands are interested in trying this, you need to have extensive knowledge on anchoring ropes/rappel routes in the outdoors. It's very dangerous if you don't know what you're doing, and you shouldn't go if no one in your group has done this before (so Nicole, tell your hubby there will be NO FAMILY TRIPS), so if you want to give it a bash, you should look up canyoneering routes/guides in your area. That way you can give the trip a try with someone experienced in the sport and the area, and you'll have someone to help you get the appropriate gear (Notice the helmets!). It's a lot of fun and very few people get the opportunity to do this, but it's extremely hard work. My pack was about sixty pounds once it was wet, and we carried about 300 feet of rope. I gained six pounds over the week (in muscle, I'm pretty sure). The trail up one canyon we did was only four miles, but it took about eight hours from start to finish. Slow but rewarding!
I'm actually not a fan of heights unless I am roped into an anchor. If I am in harness and wearing a helmet I feel better because I have confidence in my gear and abilities. The last picture was my favorite moment because I actually jumped! It was a twenty foot jump into a VERY deep pool. My husband was waiting to take my picture before I jumped, and I was sing-songing "This makes me VERY nervous!" the whole time. I'm not as brave as you think I am!
Shell, I am afraid to mtn bike because I'm not as much in control as I am in climbing and rappelling. My husband loves to mtn bike, but I have yet to try it.