In this article we focus on the widely researched motivational construct, interest, with the aim of identifying the character of positive affect associated with students' interests. There is a well-documented association between interest and students' engagement with classroom activities. It is also widely accepted that enjoyment plays a role in the dynamic processes operating when students engage with interesting learning activities. We used an innovative measure (MINE) that invites participants to explore and nominate their interests from a relatively large pool of interests. Young adolescent students (N = 213, mean age 13 years 6 months) explored this interactive space to select interests and then had the opportunity to expand on the selected interests through text comments as well as ratings on affective and experiential scales. On average students chose approximately 5 interests and we describe the distribution of interest content for these choices. As expected there were differences between boys and girls in their patterns of interests. Using the students' ratings of their interests on 7 affect terms we found that across all of the nominated interests there was a consistent pattern; high ratings of "happy," "excited," and "proud," moderate to high ratings for "hopeful," and very low ratings for the negative affect terms, "frustrated," "anxious," and "sad." This pattern was consistent across interest content and gender groups. Individual profiles of the affective responses associated with 2 students' chosen interests are described and some of the insights these profiles offer to teachers are explored. Knowledge of how specific positive feelings are active when students engage with the content of their interests will assist practitioners to understand how interests might be used to personalize learning activities and curriculum choices in the service of greater student engagement with learning.