They call you in to sit down and chat, get a feel for your qualities, experience, why you applied, who referred you, etc. They might ask a few situational questions depending on the position you're applying for, but not necessarily. The manager is different now from when I was hired but he's a chill guy. You might go in a second time for a follow-up interview/hire, if the first time was a short screening interview. They're looking for nice, down-to-earth people that don't get worked up about anything and are easy to get along with, but they don't hire slackers.