Shortest and best interview consisted of the question, "Do you have a sense of humor?" I worked for them 2 years and we're still friends 15-16 years later.
Longest was one that they had me follow people around allll day. My eyes were glazing over interspersed with rolling back in my head. I got an offer and took the job, but it was only a 3 month temporary one, to cover for someone out on maternity leave.