As my username fact that I am 24 and still working on my B.A suggests I have the same problem. When I am interested in the subject I can pay attention well. Then if the particular lecture is really boring, I can daydream about the lecture topic, like someone else was saying. If the subject is something I find really boring, I am generally screwed. I do find that chewing gum helps sometimes....or snacking....I'm not sure why. Sitting at the VERY front of the room, sometimes works too. Also ADD pills….........