The Parent Teacher Organization, or Association, consists of parents and teachers who advocate for the students. This group is the first stop in attempting to add activities to a school. This group will sponsor activities such as dances, school circuses and student meet and greets.
The school principal will know the school budget and rules for extracurricular activities. For example, some schools state that a school employee must be present at all activities sponsored by the school; other schools dictate the length of time for an activity. Approach the principal with your ideas and talk to him regarding the possibility of getting an activity started for the students.
Groups such as the Colorado High School Activities Association will sponsor, plan and conduct extra curricular activities for students. Many schools have clubs such as this one. Contact your school's secretary and ask for your local chapter information. Speak to this group regarding your activity ideas. These types of groups operate separately from the PTO and often split activity responsibilities with other associations.
If every other avenue seems to be a dead end, speak with other parents regarding your ideas. A public school system will begin to listen to a group of parents, so your activity may need the support of others. Ask the parents if they are willing to sponsor the start up fees for the activity or provide other volunteer services. Approach parents who have children interested in the activity.