I applied online, and then was contacted for a phone interview. The phone interview lasted for ~30 minutes, and the interviewer spent ~10 mins talking about the company. Next, the interviewer asked questions about my work experience and ended with a brain teaser. Pretty straightforward, as others have mentioned. At the end of the interview, the interviewer even asked me when I could start, and told me that I would be sent a homework assignment that I needed to complete within a week. They basically asked me to do the work that I'd be doing if I was hired--this definitely took longer than the 3hrs they said it would--it wasn't a hard assignment, and I actually enjoyed completing it. I took a lot of time to perfect my responses, and to do my research. I have several years of science teaching experience (both k-12 and college level), and two science degrees so I figured that I was a good fit, and that I had a good chance.
After submitting the assignment, I got a generic email that said they were "impressed with my qualifications" but that they "...have decided to proceed with other candidates who meet the company’s needs more closely." The latter sentence made me raise my eyebrow, because the position is still posted two weeks later.
Furthermore, as other reviews mentioned, this position has been posted for a WHILE--I remember seeing this job position posted in DECEMBER of 2015. Also, the interviewer told me that they don't have any designers working in this position at the NC office--thus, because of this, and because they are trying to increase their library of materials for students, one would think that they'd have hired someone by now. Especially because they interview everyone who applies! Lastly, throughout the entire process I was NEVER asked to provide references--without these, how would they even know what type of worker I am?
My advice would be to proceed with caution, and to REALLY take into account what others have said here about their experience with the interview process--something just doesn't seem right.