I can't remember where I got this from, but I like to ask them to talk to me about their favourite project. It can be school, hobby or work, just something they

I can't remember where I got this from, but I like to ask them to talk to me about their favourite project. It can be school, hobby or work, just something they are excited about. Then we talk about what made them excited, what design tradeoffs they considered, the problems they ran into, how they overcame problems, what they would do differently knowing what they know now, and so on. My favourite answer was a guy who replied "I've been working recently on some OpenGPL stuff in Common Lisp for the X window protocol". That was an interesting chat, and I was happy when he accepted the offer I made at the end of it.