The William Gates Faculty Building on the West Cambridge Site.
Are you interested in Computer Science? Here is the Faculty advice (from the FAQ's) about developing your interests for this subject:
At the admissions stage we look for two major things: academic ability and passion for the subject. Whilst the course itself does not have any pre-requisites other than mathematics, it is difficult to discern a passion for the subject if a candidate has never tried any form of Computer Science. Therefore, from an admissions perspective, it would be wise to do something that shows your independent interest in the area. Examples of this include reading around the subject, learning a programming language, contributing to open-source projects, releasing a phone app, or building hardware (robots etc). Any one of these, when done well, would be sufficient to demonstrate your passion.
If you choose to learn a new language, it may be a good idea to learn one that is not explicitly taught in the Tripos. Doing so obviously helps to avoid repetition, but also gives you a wider perspective on languages that can be useful later in the degree and in employment. A popular choice is python, for which there are many tutorials available.
We recommend getting hold of a Raspberry Pi and following one of the many hardware and software tutorials for it on the web. An additional advantage of this route is that you will gain familiarity with the UNIX command line: a very valuable skill to have in the Tripos!