Phone Screen, Genius Questions (1 week, very difficult), followed by 4 hour Skype interview. Phone screen was about 45 minutes long, genius questions were a 20 question long test (about 3 hours expended on each problem) and I could choose to do pretty much 10 of them.

Given a tour of the ECL for an informal visit before being sent a take-home exam with questions spanning different fields. The test was difficult and fairly time-consuming. After submitting my answers, received a response shortly after letting me know that they were not moving forward with the interview process.