Black, slim fit, with little pintucks, but with an appropriate rise ("lower mid-rise") makes these BeBe "Pressed Pintuck Lulu" pants (pictured left) a perfect pant for business casual offices or for casual Friday or for a quiet night out. I would wear them to the office on the weekend too if your office isn't really all that weekend casual.
The pants are made from polyester, viscose, and spandex. Originally $129, the pants are on sale for $79. They are available in sizes 00-10. Find them here.