My older one is taking fencing lessons, and he really likes it. Apparently fencing is not sword-fighting, like Errol Flynn. It's fairly cerebral and an individual sport.
We go to a local fencing academy, where the teachers are very nice and low-key. I think it could be a long-term love for my son. The older kids who are fencing come in all shapes and sizes- tall, small, overweight, skinny. With so many sports, you need to be a big kid, but I guess at least at this level, you don't need to for fencing.