Really? I went to three different summer programs at Ohio State University when I was in high school. Great fun.
My last summer program ran nine or ten weeks and had me playing RA in a biochemistry lab. One of the most generous masters' students in the whole world (I think the poor guy was in his 3rd or 4th year... he was kind of a long-term masters student ;) spent most of the summer teaching me stuff -- growing bacteria, lysing them, running chromatography columns, gels, enzyme activity assays, the works.
He was crazy, actually, to spend that much time teaching a high school junior who would never come back to the lab, but I hope he's having a happy career somewhere because he sure was generous.
Obviously, if an organized program exists, take it! My point was that the absence of such a program does not preclude you from taking an individual initiative to do something creative.