What to do...

So I started a new internship last week at a really great company, and they don't have anything for me to do. This seems like a really unusual problem, for a company this successful, so I am convinced that I need to make myself known.
To do this, I will make my rounds every morning, telling every department head that I'm here and am willing to do whatever they might ask me to do. They usually smile, thank me, and then go back to work after some small chat about how they'll let me know as soon as something comes up. Do people in office's just act like they have things to do all day, when they really don't?
Disappointing.
Another problem that I've run into is that when they do give me something to do, I finish it quickly, and then am back to square one. This dilemna could be solved by dragging out what work I get as long as possible, but that completely defeats the purpose of efficiency!
Alas, I brought my new book The Wild Things by Dave Eggers and am thuroughally enjoying it.