The mousetrap was Behe's example. He wheeled that argument out again in a talk that I went to. He claimed that the mousetrap parts couldn't have been designed without being part of the mousetrap.
Yes, BUT he was arguing from design. The mousetrap is designed. You can't respond by saying "well this is how it could have evolved" without looking really stupid.
Of course everyone knows that springs couldn't have been designed without being designed as a part of a mousetrap, since there's no other purpose that springs can be used for. Same applies to metal rods, pieces of wood, etc. That's the downfall of many of these irreducible complexity arguments. It is possible that all the parts evolved for some other function and only later became incorporated into the system that is claimed to be irreducibly complex.