Considerable evidence shows that the number line is a powerful learning tool for children in elementary school. Diezmann and Lowrie (2006) noted several cognitive advantages for users, including opportunities to demonstrate the continuity aspect of numbers as well as the provision of a useful tool for representing and solving problems. However, Diezmann and Lowrie (2006) found that many fifth graders were unsuccessful in using a number line effectively; they attributed this lack of success to students' inexperience with number lines. In this article, the authors describe an activity--for which a number line (in the form of a number roll) is a key component--that is built around the One-minute challenge game. They outline the basic game and then present a range of ways to adapt it according to content focus and student age.