Seth Godin is launching a new project soon to allow people to teach a small, free, highly-interactive class online. The link I've provided allows anyone to sign up to be updated and to potentially teach a course once the program launches. It certainly won't be the first platform to offer this service, but Godin is known for coming up with innovative ways to connect people. And he's going to attack the current problem with open online courses–97% of those who enroll don't complete the course.
Of course, there's an obvious application for students who would like to learn something interesting. But I can't think of a better way for a student to stand out in college admissions than to teach something with anyone who's interested. Why not teach a course that shares how you raise funds for your group, or generate interest in your school's activities, or organize summer workouts for your cross country team?
I don't know how the instructors and topics will be chosen. But sign up for the updates, think about what you might like to teach, and take advantage of the opportunity if it presents itself.