I just remembered an excellent post I saw somewhere ages ago, but which I now can't for the life of me track down. It was a method of fleshing out a campaign world and simultaneously producing nice bits of interesting background for characters. The idea was that for each race you have a set of tables like "most halflings X, Y, Z", "some halflings A, B, C", "rarely halflings J, K, L", and so on. That's the gist of it, I just can't quite remember the details.
If anyone knows where to find it, please do let me know!