A way to find out if people are going to fit with your team is to involve the candidate in the real process that you have with your team instead of inventing scenarios just for the interview or coming up with trick questions that supposedly tests the knowledge that they have.

During the later stages of the interview process treat them as if you hired them as a consultant to work on a specific problem for part of a day. At the later stages of the interview process both you and they should be willing to commit a good 2- to 4-hour chunk of time to the interview process. That should be sufficient time to involve them in a real meeting with the team members they would be working with to discuss and begin working on an actual problem your team is trying to solve. Yes, that takes quite a bit more preparation and planning on your side, but it will tell you a lot more about how someone thinks and works along side others than any number of interview questions you might ask.

Also, working along side others is much better than isolating them in a room with a problem to solve since their communication skills and ability to work with your team is often more valuable than any domain specific knowledge they may bring with them-- not that the latter isn't important, but it's not worth hiring the smartest person in the world if they're gonna act like a jerk and can't work with everyone else.

Something that makes this process easier is if you already use pairing stations with your current team, as is popular these days in some places. Note I said *pairing station* rather than *pair programming station*, because a pair doesn't have to be limited to just writing code-- other office disciplines can benefit from that kind of setup, as well. I don't recommend using a pairing station *just for the interview*, though! If you don't already use them in your workplace with your team, then it will be another artificial part of the interview. For the team that I manage we don't use pairing stations for everything, but I make sure that they are always available and we make use of them when it is effective to do so, so in our environment it makes sense to use it as part of the interview process.