Along similar lines as this recent post to the SitePoint PHP blog, Justin Carmony has a new post talking about types of interview questions and the "softball" ones that are commonly used.

While it seems every few months the topic of the interview process goes around the community, and I think the general consensus is most of the time it is ineffective. At DDM, there has been a lot of thought put into our interview process, and so over the next few weeks I hope to share some ideas we’ve had.

He starts with the "status-quo" of an interview that's set up to ask questions of the candidate, either by a single interviewer or a group, that focuses more on strengths and weaknesses than technical aspects. These usually include the "softball" questions that just about any PHP developer could answer. He then moves on to the more difficult follow up questions relating to specific technologies and features of the language. He also offers some advice on the questions for an interview including writing them down first and ensuring that they're short and to the point.