I use a mix of asking about what's on your resume (chronological works nicely, so I understand why you switched jobs and how your skills evolved) and a set of standard technical questions (so I can compare candidates over time). I'll usually dig deeper technically until you give up. Giving up doesn't mean failing, on the contrary.
Do you ever try to assess traits like motivation or curiosity? Do you allow those to just come out in regular conversation? Or do you just stick to the resume walkthroughs and technical questions?