Challenges and Choices are from the Reading Series and I put them into a "choice" sheet for the students to work on throughout the week. I assign the Challenges and Choices on Monday/Tuesday and they are due on Friday. Students may work on them at home, in study hall, or during our "bonus" period once per week...this allows me to help guide them and answer any questions.
We have a 40 minutes LA period. It's short. I use this to help students take their reading a step further on their own.