This is awesome! MIT has created an interesting course as part of the their Open Course Ware project: it describes how radar can work, and as a final project, students were expected to build an test a simple radar system. Their description:
Are you interested in building and testing your own imaging radar system? MIT Lincoln Laboratory offers this 3-week course in the design, fabrication, and test of a laptop-based radar sensor capable of measuring Doppler, range, and forming synthetic aperture radar (SAR) images. You do not have to be a radar engineer but it helps if you are interested in any of the following; electronics, amateur radio, physics, or electromagnetics. It is recommended that you have some familiarity with MATLAB®. Teams of three students will receive a radar kit and will attend a total of 5 sessions spanning topics from the fundamentals of radar to SAR imaging.
I haven't read a lot of this, but I'm bookmarking it for future perusal.