Nice puzzle from an Olympiad!

if a,b are integers,

q = (a^2+b^2) / (ab+1)

prove if q is an integer, q is perfect square.

Has a beautiful solution!

BBC Documentary archive

BBC has an archive of all the nice documentaries broadcast in BBC world service.
There are some very good ones:
http://news.bbc.co.uk/2/hi/programmes/documentary_archive/