Many schools and agencies offer programs over the summer for interested high school students.  This can be a great way to learn a new skill, hone a talent, or develop leadership capacity.  Often, these programs are offered for students who are intested in a particular field to get some hands-on experience.  Attached is a list of a few summer programs that I have come across.  Keep in mind that many colleges offer programs, so if you do not see something that you are interested in, you may want to check the websites of local colleges for other opportunities.