Joe, you don't have to be amazingly clever like everyone makes out you have to be to go there, you just need to work hard and make the right decisions with the application!
Indeed, Oxford and Cambridge are great places. Beautiful, in fact. Funnily enough, I'm visiting Cambridge for four days this week, staying inside the colleges.
Yeah you're right, you don't have to be amazingly clever, but I don't think I'd ever be able to push myself hard enough to get to the standards they need for entry. I mean, not to be cocky here, but I do consider myself intelligent in a way, but I think I've always struggled to apply myself when it comes to School etc.... I haven't done extremely bad by anyone's standards, but I was always content with what I got in terms of grades, usually B's and C's, and I never aimed higher when looking back on things I know if I had aimed higher and maybe revised properly I would have done so much better. I think part of it was down to always letting work get on top of me, and when I worked my ass off in an exam and got a worse result than I thought I'd get, I'd put myself down rather than re applying myself to do better the next time.
Enjoy your visit to Cambridge, not had the chance to visit there, and don't know much about it, but I'm sure it's great.