It's a new decade, and the U.S. Census Bureau is gearing up to send agents around collecting information. Now, since I'm a genealogist of sorts, I'm happy to find information on family from past censi (or censuses). However, the Constitution authorizes and enumeration for the purpose of calculating how many representative each state gets in Congress. Anything more than that is simply information gathering.
A few years ago, the U.S. Census Bureau started sending around the American Community Survey, which is "conducted under the authority of Title 13, United States Code, Sections 141 and 193", according to the ACS FAQ. A more intrustive "survey" you'll never lay eyes on, and the "law" threatens you with substantial fines if you don't answer.
However, there is a way to answer both the ACS and the Census truthfully, completely, and still maintain your privacy. Any questions that pertain to the First Amendment, that is, religion or anything pertaining thereto, can be answered, simply, "First Amendment". Anything else besides your name and address and number of people in the household can be referred to the Fourth Amendment to the U.S. Constitution, which guarantees (not grants, because this right is given by God and not government) your right to privacy. The actual wording of the Fourth Amendment can be found here.
Rights that are not claimed are not rights at all. To remain a free people, it's imperative that we "remind" our government that the U.S. Constitution is the fundamental law of the land and that Congress cannot change it merely by passing a law.