There are a lot of summer enrichment programs out there for high school students. Here is a list. Make sure you check costs, financial aid, and what age/grade is accepted.
Worcester Polytechnic Institute (WPI)
List of summer programs - http://www.wpi.edu/academics/Summer/highsc074.html
(this is where I went for my engineering degree)
Rensselaer Polytechnic Institute (RPI)
Preface Program (engineering/tech): http://doso.rpi.edu/update.do?catcenterkey=87
List of summer programs - http://summer.rpi.edu/update.do?catcenterkey=4
University of Connecticut (UCONN)
BRIDGE program (for students interested in engineering) - http://www.engr.uconn.edu/bridgepreparestudents.php
Check these out - see if there is something that you are interested in. These programs can help you prepare for college.