1.) Have a week without using any gadgets to conserve electrical energy.
2.) Be active in environmental organizations to help regain ecological balance in the area.
3.) Be a volunteer in helping children who cannot afford to go to school to make their parents realize how important it is to make their children have a good education.
4.) Earn money for charity with their peers in order to help those who are in need.
5.) Make a committee/organization that prevents bullying at school so as to avoid exposing other students to violence of any kind.
6.) Have a weekend tutoring service for other students who have difficulty learning.
That's all I can give you :) perhaps you should also state your ideas and solutions regarding youth challenges. You can also base some of your ideas on the problems in your area. I wish you the best of luck!