So I've been helping with recruitment at work for a lead developer. Our first stage is pretty standard for all levels and it essentially a technical interview because CVs are useless really. We're a C# house so we have questions on framework internals such as how the dictionary class is implemented, locking and thread synchronization techniques. Then some pen and paper coding excercises, like reverse array.

I'm not a big fan of these and I think they are too constrained to detail implementations and not about concepts.

So I ask what stuff do you do at your company to get an idea of some ones competency?