Teachers often use in-class questions to examine the level of understanding of their students, while these also enable students to reorganize their acquired knowledge. However, previous studies have shown that students may resist being questioned because of negative emotions. Therefore, this paper proposes the idea of eliciting positive emotions by showing students funny images to reward them for providing correct answers. Three studies were conducted with different courses, using either a video lecture or classroom lecture. The results of Study 1 indicated that 22 learners who watched 10 financial literacy video segments and were rewarded with funny images tended to have more positive emotions, an upward trend in their attention levels, and greater test scores as compared to the other 22 learners watching the same videos who received no rewards. Studies 2 and 3 were conducted in the data structure and computer networks courses, respectively. With regard to affective states, the 52 students in the two courses gained more learning confidence in classes that providing the amusing stimuli as compared to those without such rewards. However, only students in the computer networks course had higher test scores on their mid-term exams when answering rewarded questions compared to when they answered those questions without rewards, although this was not found with the students in the data structure course. The findings suggest that rewarding students with amusing stimuli can enhance students' affective states, even though this instructional strategy does not lead to higher learning performance all the time.