Multi-part interview. The first part was an initial phone screen with your standard questions (work history, goals, what they are looking for etc), then a second phone interview with more detailed questions (scenarios). Then got flown in for a group interview for the final part. (4 candidates at the same time) This process went all day and included group discussion, individual interviews and a case study. Finally at the end of the day you had to do an one minute "elevator pitch" why you are the right candidate.
They then never followed up with final decisions even a courtesy email or phone call saying thanks for your time. They are such busy a business they could not send three regret emails? It is a poor manners