Section 102(b) of the Copyright Acts states that "In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work."
In other words, ideas and facts are not copyrightable nor are speeches (until written down). The item must be in a "tangible form of expression" before a copyright can be attached to it.
Items used commonly - such as a calendar or a list without creativity - like a phone book, are also not eligible for copyright protection.
Another type of material that is not covered by copyright are government documents. These include bills, laws, congressional reports, census studies and all other types of material published by the federal government in involved in publishing.