Contribution: This paper shows that participating in a year-round program for African-American male middle school students (ages 10-14) can positively impact their attitudes toward STEM, their confidence in problem solving and team work, and their interest in STEM careers, but may not impact the interest in taking STEM classes to the same extent. Background: Increasing the number of under-represented minorities pursuing degrees in science and engineering through formal and informal learning activities has been a focus in the United States for many years. Efforts to diversify the engineering workforce have often targeted students in high school and college (ages 15-22), with varying success. Intended Outcomes: This program was designed to increase participants' content knowledge, interest in STEM courses, interest in STEM careers, interest in attending college, and improve their attitudes about STEM. Application Design: Approaches used included: 1) introducing software tools that encouraged critical thinking, creativity and independent learning; 2) integrating engineering and software design processes; 3) providing projects that were age- and culturally-appropriate; and 4) using ethnically matched mentors. Findings: After almost two years in the program participants show improved attitudes toward STEM, more interest and career choices in computing and engineering, and increased interest in attending college. These findings suggested that summer and academic year programs can be effective for cultivating interest in computing and engineering careers, but their impact on interest in studying related subjects may need further study.