It was on an on-campus interview, lasted roughly 30 minutes. They asked me general behavioral questions, and one question that was unique: "How many ping pong balls do you think you can fit inside the football stadium?" I wasn't sure what they were expecting as an answer from this question, so I probably didn't give them what they were looking for.

It was an on campus interview. At first they asked a few behavioral questions about working with a team and then asked some technical questions.They gave me a drawing of a pressurized vessel and asked what kinds of forces are applied on it, etc. Be prepared for both.