I did part of an orienteering course on Saturday and it was great fun. I have done them before but it seems I always forget how much I like doing it. Not only is it fun, but it has great training value. Unlike just going for a hike where you stay on trails, with orienteering, there is no trail. You simply have a map and compass. It is up to you to break brush until you find your flags.
The two courses that I have easy access to have some pretty steep terrain (for this part of the country) and heavy underbrush. You will find yourself exercising your brain and your body. It can be very challenging and rewarding to find your flags. It is definitely not just a typical walk in the woods.
If you are lucky enough to have an orienteering course near by, I strongly suggest that you take a buddy and spend an afternoon brushing up on your map and compass skills.