Being a recent graduate of computer science and now job hunting I have come across several different types of interviews in the last few months. I have sat a coding test where they just asked me to write a very basic CRUD application in code igniter, also had the here is a scenario you have 15 minutes to write a presentation and then present us with your result, plus an interview where I was asked to do some UML on a whiteboard.
But the best method I have come across was where I was just asked 20 or so questions of basic computer science knowledge from OOP to networking to basic CS theory.
I say this was my favourite method because I know some recent graduates who could and can write a very simple application but are terrible programmers and would not last the probationary period (actually happened to someone I know) but I know that if you asked them a series of basic questions they would stumble and fall because in general they where just terrible computer scientists and once outside of the very basic elements of programming they knew nothing so what good does asking someone to write fizzbuzz actually do? apart from weed out the idiots (then again I know someone else who failed fizzbuzz, largely because he managed to get through 3 years of CS and not know about using %).