I'm not always willing to devote the required time to training for marathons+, so I only do them every other year or two. Who can make the time to do 100 milers? It also interferes with my riding, as I haven't figured out a way to leave a thousand dollars of leather and helmet on my bike while I'm gone running for two hours, and expect to have it still there intact when I get back. I like knowing I can run 31 miles. There's one here in Oregon in September that I ran in 2005 and loved it:
http://mrtr.org/That's not the one where I injured myself.
It's a good excuse to do the Crater Lake marathon a month before that, too, for a training run. :-)
If you like fencing you might enjoy other martial arts like karate or taekwon do: also very intense workouts, but so facinating that you can't stop. Well, besides the fact that you would get beat up. Just kidding! They are probably better for you as they utilize your body in more versatile ways, not just legs and right arm. Assuming the yoga gets you back strong and limber, of course. I should learn more yoga; I just use it as a warm up for doing my forms.