No not apps, but Advanced Placement classes! If you get the chance to take an AP course in high school, take it, because it sure does pay off in college! For example, as an aspiring political science major I thought that out of all my high school AP courses only history and English would exempt me from college courses. However, during a meeting with my academic advisor, she pointed out that political science majors do need to take math courses, and since I took Calculus in high school, instead of three semesters of math I only need two! YAY (I mostly rejoice because math is not that easy for me)!
Nonetheless, the message that I am trying to convey is that AP classes not only give you college credit but they also give you much more flexibility in college. In doing so, allowing you to take more of the classes you want to take and less required classes. So take them if you can, they do pay off!