Class preparation is recommended by instructors in most college courses, but checking whether a student does so is not easy. A new blended learning system, named ClassPrep, has been proposed and implemented. The usability of the system was examined for two undergraduate psychology courses: one advanced course (n = 11) and one introductory course (n = 59). In these courses, students were required to prepare for class through a series of activities. The first activity was to write a one-page essay based on the assigned reading material. Another activity was to come up with three questions related to the material. The third activity was to review four essays written by peers, which were delivered by the ClassPrep system anonymously. The last activity was to evaluate peer review scores and comments. All these activities were to be done before class. During class, lectures were minimized. Instead, the students and the instructor worked together to answer some of the questions raised, discuss some other questions and review a few selected essays. Analyses of the survey on the system and the official course evaluation revealed that students' responses to the system were positive overall. The implications of the results and future research directions are discussed.