Fitness Hobby Needed

Hi all,

I'm looking to start a new hobby of some kind which will also act as further exercise.

I love playing squash, however the only courts in travelling distance from my home are always fully booked up, so unfortunately that's looking like a no-go.

I've been contemplating some form of martial arts, such as karate, ju-jitsu, kick boxing or similar. Has anyone ever done any of these for a considerable length of time and are they something that you would consider hard exercise (which is what I'm looking for, I won't be shying away if it is hard)

Thanks