Officially our best-ever cease and desist
The sad thing is, the NPB may have had a valid point here. Unlike most forms of intellectual property, trademark rights <i>do</i> degrade if you don't defend the mark and it is deemed to be diluted. I'm not sure the ThinkGeek guys got this, since they referred to parody as a defence, and that would normally be used in connection with copyright. So we can all have a good laugh, but there might be a real point about the appropriateness of various legal standards for defending intellectual property rights as well.