Most schools have committees that require teacher participation. Usually teachers have to be a part of at least one committee, so you will probably be assigned to or asked to join a committee during your first week of school or even earlier. If you are assigned to a committee, then you just have to deal with whatever committee is given to you.
However, if you are allowed to choose, realize that not all committees require the same amount of work. If you can, try to pull aside a veteran teacher and ask her opinion about each committee's workload. You may find that the Testing Committee requires many hours of work while the Technology Committee does not.
Even with this information, you may not get the assignment you ask for. If you can, limit your committee membership to just one committee. In other words, you might not be able to say “no” to two committees if asked, but do not volunteer to join a second committee.
When making decisions concerning your career, it is a good idea to think in terms of the long run. Even though committees and other activities may seem trivial or even a nuisance, they can create situations that could lead you closer to your goals.
Once committee work begins, you may find that other members turn to you with extra work. While it is expected that as a committee member you will fully participate, you should speak with your committee leader if you feel that you are given the majority of the work. If you are very agreeable to everything without ever speaking up, you will be taken advantage of. This is especially the case if you are not only agreeable but also efficient. People who are known as hard workers usually get the most work.
However, if you do have the time and the interest to get involved, then you can make a real reputation for yourself at your school. If you have a goal to become an administrator, then you might want to consider joining a committee that gets you noticed. Committees vary in all schools, but some are more prestigious than others. These are the ones that wield more power in the day-to-day running of the school.