First, I was chosen for a phone screening type interview with the recruiter/HR person.
Next, I was brought in for a 1:1 interview with my immediate supervisor to go over my resume and background and skill set early on a Friday morning.
I was called later that day and was asked to come back (same day) for a group interview during Happy Hour to see if I was a good culture fit.
I did not know what to expect so I wore a suit for the first interview, but jeans and a blouse for the more casual happy hour interview.