Although, now that I'm an interviewer, I kind of despise FizzBuzz, because nobody thinks clearly during a high pressure interview.
Whenever possible, I love to talk with a candidate about some concrete past source code they claim to have written. I've better luck putting the candidate at ease and then talking through their contributions to the code.
Of course, when I get enough candidates who shared source code, I don't even invite the ones who didn't share source code for an interview.
I thought my entrance test was far too easy, I only had to create a blog in my web framework and show doing the basics like validations, secure parameters, etc.
I learned later on that most couldn’t pass because they came from other languages and thought they could get by without knowing anything.
I wrote "some code" back when I was a child, if you asked me to explain how it works all I could tell you is "through the power of santa's little helper".