Have you ever stared up at the Stratosphere’s slender cement tower and thought, Man, I’d like to climb those stairs? No? That’s because most sane people don’t climb 1,455 steps when there’s a perfectly good elevator waiting to whisk them into the sky. This weekend, however, sanity comes with a side of rock-solid calves and a penchant for taking on challenges in the name of charity. Stair-climbing savants and motivated Average Joes will race up the equivalent of 108 floors inside the Stratosphere tower core as part of the Scale the Strat lung disease benefit, with all climbers heading up Saturday and the top 50 competing for prizes on Sunday. Think you’ve got what it takes? Register online before Friday at noon or head to the event early to be one of the first walk-ins.