It was quite fun, actually. I spoke with the hiring manager and we talked about the job, co-workers, physical location, work atmosphere and more. We were scheduled for 45 minutes but we spoke for nearly an hour.
I'm giving the interview a thumbs down because I never heard back from them. I appreciate that this was going to be a competitive process and I'd be up against some stellar applicants, but to speak to someone for nearly an hour and not hear back -- not even a generic "sorry we're not moving forward with your application" email -- is unacceptable. Do better, Smithsonian.