Athletics and sports are the most obvious examples of college extracurricular activities. All colleges run some level of athletics club, as well as a variety of sports teams. Even if you are not a star athlete, and you do not think you will get in the team, you can compete at some level. Most colleges run an inter-mural sports league for people who are interested in competing, but who are not good enough to get onto the college sports team. If you want to do a sport that is not available, colleges usually will help you start a club.
Colleges run bands and different music societies. As with sport, this is usually for students of all abilities. For example, if you are able to play the piano at a novice level, there will be a club that you can join. Furthermore, colleges usually have music or arts representatives, with whom you can arrange to start a club.
Student government exists throughout your educational career, and this is even more the case at college level, when student government covers all areas of college life. If you are interested in running for election, then you will need to attend meetings of your student government, and find out how the process works. Holding an office in student government allows you to meet with the college administration and make real changes for the lives of your fellow students.
Many colleges have strong ties to the local communities, which manifest themselves in local volunteering organizations. Many colleges place a great deal of credence on their involvement with these projects, and doing so will greatly benefit yourself, your college and the local area. Depending on your area of interest, you can find a volunteering project to fit your interests, whether it be teaching at a local school, working on an environmental project or some other area. Volunteering projects are extremely common throughout U.S. colleges.