Weekend Discomfort: 53 Fun, Challenging, and Uncomfortable Ruck Workouts to Help You Suffer in Style: Nadoroznick, Riley: 9798410828345: Amazon.com: Books
Run the Gauntlet Challenge | Know Your Meme
Kilter Miles for Meaning Challenge - The Kirk Gibson Foundation for Parkinson's
Daily challenge for students to try to decipher definition by knowing meaning of root, prefix, or suffix
Challenge definition and meaning | Collins English Dictionary