After a phone interview where I rated myself on software skills, I was asked to do a 2-part test -- writing a letter to a donor, and designing a flyer for an event, which took me several hours, as they both required additional factual research to complete. A couple of weeks later, I was asked to come in for a one-hour interview with two people. They asked some very peculiar generic questions, such as "What tools do you need to be successful?", which I didn't feel were relevant. Later, they asked job-specific questions, such as how I designed the flyer, and how I would set up a travelling photo exhibition. I asked them how they managed having exactly as many unpaid interns as paid employees, and they got incredibly defensive, saying their internship program was very competitive, when all I wanted to know was how long the interns were there for, who was responsible for all of them, what kinds of tasks they did, etc. Having dozens of interns implies they rely on them quite a bit for professional work, but must have constant turnover of institutional knowledge.
They said they would make an offer and notify all the candidates later that same week. One week later, I e-mailed. Two weeks later, I left a voicemail. Four weeks later, I finally got a hold of someone else who told me the position had been filled. After all the time I spent on the interview process (esp. as it was only a low-paid, part-time job), I felt this was unprofessional.