I was contacted by a recruiter, and there were three phone interviews in total. It was overall a really positive experience - the recruiter was really friendly and helpful, and the phone interviews each lasted about 45 mins, with 15 mins for me to ask any questions I had.
I got an email from the recruiter asking if I would be interested in product design opportunities, and then there was a screening call in which she gathered some basic information about me, asked a few questions about my work experience and skill set, explained the interview process and answered any queries I had. Then a few days later I received an email scheduling the next phone interview.
The interviewer was a designer at Facebook - pretty friendly, and explained what he was currently working on, and then asked me what phone I was using. Then I was asked to put on headphones and keep the phone in front of me and answer very specific questions for about half an hour, about iOS settings, and methods of measuring user engagement, etc. There was also a hypothetical design problem given to me, and I had to then defend my design decisions and justify why I chose each interaction that I did.
The next interview was scheduled a couple of weeks later, and that was supposed to be a critique of my work - but it was pretty conversational, and basically an opportunity for me to explain recent projects that I had enjoyed most. And on a specific project, I was asked to explain at length my design process and UX decisions, and whether there was anything I would have done differently. This was also followed by a friendly discussion of the work culture, and I was asked if I had any questions. Didn't make it to the on-site interview (which would have been a presentation of work, followed by interviews with a panel of five people), but it was overall an enjoyable experience, having to think on your feet etc.
