Eliminating Boredom of Online Lectures

I love learning, and I want to study more, so I went to Udacity.com, and Coursera.org. Unfortunately, I found watching lectures terribly boring. Although I can focus on listening and understanding them well, it is not my preferred mode of learning. My preference is -- to dig and explore rather than watch and listen. I started asking: why do I find it effortless to focus on watching a 1.5 hour detective film or a TED talk which tells a story, but I don't get the same pleasure from watching a lecture?