What are extracurricular activities I can be involved in as an alternative to a sport?

Kim makes some great points and good direction. I'm going to add a sports angle. All teams needs some behind the scenes help. Consider being a stats person for a team. Ask coaches if they need a team manager. Perhaps work a scoreboard for a sport you like. Whoever runs the intramural sports of the school, ask if you can help organize the teams or schedules or game day administration. Most sports need help on game days (setting up the field, getting equipment to the field or court, working a ticket booth). Explore some of those options of your favorite sport. All the best and most of all make it fun.

Go with what you are interested in.  There are always clubs and programs available ranging from theater to newspaper to audio visual to tutoring.  If you want to go the sports route you can always be a manager, trainer or statistician.  Take a good look at what you are passionate about and match up those interest.  The guidance department is another area that can help give direction.  It is great to stay involved and follow your interests.

Hello! This is a great question. I would suggest seeking out clubs or organizations that align with your interests. For example, if you are interested in politics, you may want to join a student government association at your school. If you are in arts/music, your school may have a club or group who focus on these types of activities. Good luck in your search!