Before the development of mountain climbing, humankind courted excitement by tickling sleeping mastodons and bluffing during an all-in poker match with angry mastodons. Enjoy a safer adrenaline kick with today's deal: for $19, you get one Indoor Rock 101 beginning rock-climbing lesson at Gravity Climbing Gym on Frid Street (a $38 value).

The grappling gurus at Gravity Climbing Gym take a friendly approach to instruction during their Indoor Rock 101 class, stressing fun over heights achieved and safety over everything. Knowledgeable instructors outfit ascendant amateurs in a harness and shoes before showing them the ropes, knots, and belay skills required to scale with safety and success. Like medical school, a single lesson at Gravity equips students with enough information to strike out on their own. After completing the lesson, newly christened climbers are free to roam the gym and test their technique on Gravity's varied climbing walls.

As the direct descendents of mountain goats, humans have long desired to scale the tallest thing around them, be it a mountain or a wedding cake. Enjoy the aptitude necessary to obey evolution's compulsions. Classes take place on Tuesday and Thursday evenings at 6 p.m. and on Saturdays at noon. Save time now by printing and signing Gravity's release form.