This is called Timex tagging. See http://www.timeml.org/ http://www.timeml.org/ etc. I believe DARPA runs some sort of competition every year or so where diffe

This is called Timex tagging. See http://www.timeml.org/ http://www.timeml.org/ etc. I believe DARPA runs some sort of competition every year or so where different algorithms are submitted to extract temporal data from text.