[snicky]

An interview for a backend dev position with a CTO where the only technical question I had to answer was "how would you design a messaging service?". Looking back I find those open-ended system design questions best. They allow you to show your expertise and understanding in various topics and the dynamics of a meeting where you discuss some architectural challenges makes you feel like a partner in the discussion rather than a student during an exam. It resembles real life work environment situations much better than solving riddles or answering some framework-specific questions. It's also two-sided - you may learn as much about the interviewer as they learn about you. Another thing is that it just takes 20-30 minutes and you're done.