Presentation, multiple hour long sessions. Double teamed by company technical experts, for multiple 'technical skills evaluation' sessions. Good if you're good at pop quizzes, bad if you're more of a thoughtful, behind the scenes "take problem, and methodically and quickly find the answer, and carry out rigorous solution and testing" type of person.

Long interview including a presentation for a large team. The presentation was an hour long presentation about something I was an expert in and then a question and answer section. Then breaking up into smaller team interviews with 2-3 people for an hour each. In total it was a full day of interviews.