If you're looking to add some challenge to your trail rides, the sport of Competitive Mounted Orienteering might be for you.
Competitive Mounted Orienteering, or CMO, is known as the "thinking horse sport". Rather than just riding from point A to point B, competitors are given a map, marked with the approximate location of a number of "Objective Stations" that they have to find. It's sort of like a scavenger or treasure hunt on horseback.
The idea is ride out with map and compass and follow the clues and compass headings to locate as many of the Objective Stations as you can in the shortest possible time. Usually a six hour limit is set, for safety reasons.
The Objective Stations are 9-inch paper plates with numbers written on them. Riders collect the numbers and mark them on the back of their maps as proof that they located the Objective Stations.
This sport is open to all breeds of horse and english and western riders. Even newcomers to the sport are given a good chance of success as each event includes an introduction to using the compass to locate the Objective Stations and a trial run before the competition starts.
Obviously, both you and your horse will need to be reasonably fit. Your horse should be capable of negotiating a variety of obstacles, such as crossing streams etc. You yourself should be able to mount and dismount without assistance, since you may need to dismount on course.
If you're looking for ways to enjoy a fun day out with your horse, travelling over varied terrain, Competitive Mounted Orienteering could be the answer.
For more information, check the NACMO Web site.