Amendment Three: No soldier shall, in time of peace be quartered in any house, without the consent of the owner, nor in time of war, but in a manner to be prescribed by law.
During times of peace, people cannot be forced to house or feed soldiers. During a war, people can only be asked to do this if Congress passes a law allowing it.
Today this is the only one of the first ten amendment which has never been brought to the Supreme Court. It is the least litigated of the first ten amendments. The amendment does not seem relevant today since the government has never asked private citizens to quarter, or house, anyone from the military.