[madeofpalk]

We use a variation: the scenario is that us, the interviewer, is a junior developer and we've submitted our code for code review. Then later we ask the candidate to add some trivial functionality.

We've found this works really well. There are unit tests, so its always a promising sign if they go for them first. Depending on what they pick up, change or ask questions about, lets us a lot about the candidate.

[julianz]

Yep we've used a page of code from one of our systems and asked the person to talk through what they can see, what it does, what they would ask further questions about and so on. It almost instantly separates people who know a bit about code from those who don't, as the latter will literally just stare at the page for a while before giving up.

[Corrado]

I really like this idea and think it would work wonderfully for me. Plant a couple of easy-to-spot errors in there as well as some more difficult optimizations and see who finds them. :) It takes the pressure away from writing new code, doesn't require a computer, and still allows you to see the thought process of the interviewee.