You're sitting in front of a machine that can, in milliseconds, give you access to all accumulated knowledge of the human race from the beginning of its recorded history... and you're bored. People fascinate me sometimes
When you run out of things you know, you don't know what new things you want to get to know. You also don't want to get too invested, or you might lose track of time and miss a scheduled event (e.g. college class). I find myself having to kill time quite frequently.
To tell you the truth, I'm bored at the moment. I have like 10 days left of my spring holidays and I can't find anything to do. The last 7 days I've been sitting in front of my laptop - either staring at the screen, browsing the C++ forums or watching some Anime. Access to knowledge is something else. Knowledge is divided into many categories; people are interested in some which they will look into frequently. And besides, its not always fun to read. You'll get more bored than you were before if you read and read the whole day ;).