California State Summer School for Mathematics and Science
The California State Summer School for Mathematics and Science (COSMOS) is a 4-week residential summer program located on four UC Campuses (Davis, Irvine, SD, and SC) for students interested in math and science.
Students enroll in one of nine core classes called "clusters," with 18-24 students per cluster. Students research and present a final group project at the end of the program.
Tuition in 2014 is $3100 for California residents and $6000 for non-California residents. Financial aid is available.
You can find out more information here: http://www.jacobsschool.ucsd.edu/cosmos/