The Ballpoint pen is almost always with you. It can serve as a sketching tool, without additional equipment. We all doodle with the ballpoint pen. If not for those endles meetings and the ballpoint pen, a large number of doodles would never have made their way out of their creators.
Here is a great website by Jerry Stith, dedicated to this fascinating art, to show what's possible with this medium. Works by various artists can be found here.
