Challenges in Beanstack are based on tracking reading and/or activities and earning badges that represent specific milestones based on what someone has read or done. Upon reaching a milestone, e.g., 1 hour of reading, a reader will earn a badge that pops up on their screen.
In Beanstack, all challenges rely on badges. When someone reads "x" minutes or books, that person earns a badge. When they read "x" more minutes, they earn a new badge. And/or, if someone completes "x" activities, they earn a badge. Sometimes those prizes are attached to badges, and sometimes they are not. The administrator setting up your site chooses the milestones at which a reader receives a badge as well as the badge image and possible prize attached to the badge.
Video of the reader experience: