Contacted by an HR rep who did a quick 30 minute phone screening, mostly to tell about the position and ask basic questions about skills and experience. Next day, followed by a more formal phone interview with the hiring manager, mostly personality questions.
A week later, had a 3 hour interview day at location that's mostly technical. There was a simple written test, a pseudocoding challenge, and a chance to find a bug in some software. Ultimately, the technical questions are focused on your logic and thought process.
The interviewers are all very friendly, they do their best to make you comfortable when answering questions. Finally at the end there was a panel interview with 5 people, everyone was nice and it was ultimately quite casual. No trick questions, mostly just chatting.