Here are some web sites that contain business ideas for prospective high school student entrepreneurs. Feel free to comment or add your own suggestions…
http://www.valueofcollege.com/index.php/high-school-grads-starting-a-business
http://mikemichalowicz.com/the-37-greatest-business-ideas-for-young-entrepreneurs/
http://www.businessinsider.com/10-awesome-business-ideas-for-the-teen-entrepreneur-2011-2?op=1