Old Man Mountain was one of the oldest and largest Native American sacred sites in Colorado for more than 5,000 years. It is one of only three documented Colorado vision-quest sites, used by natives who would travel great distances and fast for several days upon the mountain peak as they awaited a divine message. The Ute used it up until the 1800s. Now it is a moderately challenging rock climb mostly enjoyed by locals.
Take a strong, directional flashlight with you as some of the tacks are far apart. If you can't find the next one, try shifting a little from side to side, but don't leave the tack until you see the next one. The final is marked with two tacks. This shouldn't take more than about 45 mins. I also don't recommend you go alone since there are lions and bears about, not to mention the Old Man himself might get you!