As someone who did Crossfit for two years, I can say a few things about it. First it made me think I was going to die most days, it made me proud that I survived it five days a week and I was in the best shape of my life.
Now that being said, I am a few years older and I now prefer a less intense workout. I enjoy riding my bike and taking walks on sunny days. However I also do some form of exercise everyday. I enjoy the elliptical machine and jumping rope for my shots of cardio. I love the ab mat for sit ups. This is what we used in Crossfit and it really works on saving your lower back and allowing you to really push for the intense ab definition. Check it out at Rouge Fitness and get it for less than $30. It is well worth the price. Make sure to avoid carpet burn and use your yoga mat while doing the sit ups.