During my PhD, I was heavily involved in the Warrior Scholar Project (WSP) and MITES Semester (formerly MOSTEC).
WSP is a program to help transition veterans to higher education. Each summer, colleges across the country host veterans in various stages of their academic careers (considering applying to college, accepted, or recently started) for a week-long bootcamp to learn either STEM or humanities skills and study techniques. I assist in the MIT STEM week by running a workshop introducing students to the basics of computational research. I teach the basics of Python and how to model physical systems like springs and double pendulums. The workshop I run can be found here. It's designed to take 8-10 hours.
MITES Semester is run by the MIT Office of Engineering Outreach Programs to help rising high school seniors from underrepresented backgrounds excel as they apply to college. I assist in the academic phase of the program by teaching (or co-teaching) a six-week astronomy course to roughly twenty students each summer. I design curriculum and provide feedback to students as they learn basic astronomy and research skills and mentor them as they embark on their scientific careers. Each student completes a small research project by the end of the summer in addition to standard homework assignments. Here is a workshop I developed as part of the course to demonstrate the basics of galaxy simulation analysis. It's intended to take about one hour.