The most recent information had Duke Nukem Forever releasing in early 2011. Feb. 1, 2011 is a Tuesday, the traditional release day for video games in North America; it is not the end of a financial quarter. It may be a placeholder date. I've emailed a Gearbox contact to ask for further comment.
Update: A Gearbox representative says any date out there is a placeholder only.
Duke Nukem Forever [Site]