In this study, two common classroom experiences--boredom and challenge--and their relationship with positive and negative emotions were explored. The purpose of Study One was to establish whether students associate boredom and challenge with positive or negative emotions, as well as to determine whether there are any grade-level differences in students' perceptions of boredom and challenge. In Study Two, semi-structured interviews were then conducted to elicit students' interpretations of boredom and challenge in their classrooms. Boredom was related to negative emotions, and students reported that inactive, uninteresting, and repetitive classroom activities were most boring. Challenging classroom experiences were found to be related to positive emotions, and students reported that challenging classroom experiences are related to feeling that the teacher cares about students' thoughtful and effortful work. Differences between students' negative responses to an item using the word 'challenge' and the positive associations with challenging classroom experiences indicate that middle school students perceive 'challenge' and challenging classroom experiences differently.