- Activities Programming Board (APB): Students help plan weekend activities and raise school spirit.
- Chess Club: For students interested in playing chess, possibly competitively, with other schools.
- Debate Team: Debaters test their skills against each other and in interscholastic competition. NMH has won the two-person team competition at the Parliamentary Extemporaneous Novice Debate Tournament at St. Sebastian’s School, beating 56 teams from 18 independent schools. At another tournament at the Hotchkiss School, an NMH pair took third place among 66 teams from 16 schools.
- GEECS: Group for Electrical Engineering and Computer Science
- The NMH Math Team won the 2011 Worcester Polytechnic Institute Invitational Mathematics Meet in October, beating out 82 schools.
- Student delegates of the Model United Nations attend conferences in Qatar and Egypt. In past years the Model UN has debated in Chicago, Russia, Brazil, China, and Jordan.
- At the NMH Farm, students use work job hours to press cider, make maple syrup, harvest vegetables and flowers for drying, work in the greenhouse, and drive horses.
- In NMH Outreach, students volunteer in a variety of community projects and programs. These range from long-term commitments—such as working with small children in the Big Brothers Big Sisters program—to programs like Community Meals that occur once per term. Students also participate in special one-day events, like the Winter Wonderland charity fundraiser or the Connecticut River Clean-up.
- Peer Educators receive training in health education to help their peers make healthy and safe choices. As Peer Eds, students serve as a resource for others and even develop informative and interactive workshops.
- The mission of Student Congress is to improve academic and residential life at school by integrating student perspectives into the administrative process. Student Congress is elected by house and class, and day student representatives are elected at a day student meeting.
- WNMH Radio 91.5 FM: The school’s FM radio station broadcasts 24 hours every day to campus and the tri-state area, with student DJs.