Back in 2007 I was approached to interview at Google and went through about 20 phone interviews and was flown quarter of the way around the planet for a day of interviews, but in the end there was no offer.
In early 2012 they contacted me again, but my wife had just been diagnosed with breast cancer so I told them no.
In July 2013 I was contacted again as "you've previously interviewed" and would I like to attend an "SRE Classroom" event in Dublin.
I said yes, at which point they pulled a "bait and switch" and I got passed over to a recruiter who would arrange a phone interview to check my technical skills - in this case it was "Java Coding", which had not been previously assessed because I only started learning Java in 2010.
Unfortunately I was unable to do the interview as I was travelling and the hotel internet failed just when I needed it most. It was rescheduled for a couple of weeks later when I was back home.
Even more unfortunately, after I passed the coding interview there was only about 4 days to arrange travel halfway around the world, so I didn't make it to the "SRE Classroom" event after all. Later in the month I was travelling to Prague anyway though, so I extended that trip to Europe and allowed Google to fly me to Dublin from Prague for a day of interviews.
Then the day of interviews:
1x Project management (Focused on a scenario)
1x Troubleshooting and Problem Solving
1x Practical Coding in (Java)
1x Lunch with a Google SRE Engineer
1x Non Abstract Large System Design
1x Leadership and Past Work Experience
I also mentioned to the recruiter that I had a very good friend who worked for Google, previously in Dublin and now in New York. The recruiter asked me to get my friend to chime in with his opinions on the process - it turns out his recommendation was probably the clincher.
I returned home and a few weeks later the process proceeded to the hiring committee. They declared one of the interviews a write-off, and that there would need to be a repeat (Large Systems Design) which occurred over the telephone. I think I nailed it that time, and the hiring committee approved things.
I then needed to provide a bunch of information, including anticipated availability, expected salary, current remuneration, references from two people who had managed me previously, ...
A week later they made an offer.