Because you never know when you'll end up scaling Teddy Roosevelt’s nose on Mt. Rushmore, today's Groupon to Earth Treks gets you a $17 Introduction to Climbing class, a $35 value. Courses include the use of all required climbing gear.

Your three-hour introductory course will teach you the fundamentals of knot tying, belaying, and climbing. Classes are available at Earth Treks' indoor climbing centers (in Columbia and Timonium) on weeknight and weekends. Once you've learned the ropes, pulleys, and sinister footholds, you'll have all the knowledge you need to create a wicked Rube Goldberg machine, perfect for making breakfast or creating a perpetual-motion machine.

Climbing in a rock gym is nothing like grappling the plywood-and-plastic climbing walls at a company picnic or dentist’s office. Rock gym walls are covered with state-of-the-art textured products that mimic the conditions of real rocks (indentions, protrusions, overhangs, underhangs, and cracks included). Veteran climbers say rock climbing is sort of like training and running a marathon, but you get the adrenaline rush in shorter, more intensely concentrated spurts and without all that unpopular running.

Reviews

Eight Yelpers give the Columbia location of Earth Treks Climbing Center an average of 3.5 stars:

• The employees are funny and clearly enjoy being there. It is often that you will be climbing side-by-side with them as they work. Everyone who climbs there is great at helping you out (if you want it) and working on problems with you. – Brandon D.
• Worth heading to if you're athletic and up for a challenge. It's a great full body workout (even if you're already a "beast"). – Angela Z.