Section 34g of the iTunes Terms of Service prohibits you from using the iTunes software to develop weapons of mass destruction. Really. You can go check. For those of you who can't wait, below is the exact text.
"g. You may not use or otherwise export or re-export the Licensed Application except as authorized by United States law and the laws of the jurisdiction in which the Licensed Application was obtained. In particular, but without limitation, the Licensed Application may not be exported or re-exported (a) into any U.S. embargoed countries or (b) to anyone on the U.S. Treasury Department's list of Specially Designated Nationals or the U.S. Department of Commerce Denied Persons List or Entity List. By using the Licensed Application, you represent and warrant that you are not located in any such country or on any such list. You also agree that you will not use these products for any purposes prohibited by United States law, including, without limitation, the development, design, manufacture or production of nuclear, missiles, or chemical or biological weapons."
While we are all feeling more secure knowing that Apple, Inc is working to protect us from terrorists, the more mundane reason for this patriotic boilerplate is Apple's eagerness to protect itself from government bureaucrats. In the last decade, numerous laws have been passed to keep some types of software away from hostile nations. For example, some forms of encryption are classified as "munitions" so that their export is covered by the many regulations that govern the export of weapons. But the government has also become aware that some types of software can be used to create weapons. Supercomputers, and the software that runs them, are necessary for creating nuclear weapons, and many chemical and biological weapons, not to mention advanced aircraft and warships.
Then again, it may be that the CIA has discovered that iPods, and the iTunes software that supports those devices, makes weapons developers more effective. Then again, maybe not. In any event, terms of service documents have entered the realm of entertainment. Or maybe lawyers really do have a sense of humor.