Usually I start to sing anime openings or endings in my head or I start to think about some anime which left some questions. So I'm thinking and not daydreaming although I think completely wrong things xD
I doodle mean things about the class or random doodlings. If nothing comes to mind I make a list of things I should do after class (laundry, dishes, errands), a possible paper topic or what the weekend/Thursday-Sunday will entail...
I don't usually use a computer in classes, old fashioned I know. I tend to find my classes interesting in some way so I'm not usually bored.
I mess with whatever objects I have near me. I try to not be annoying, but sometimes I can't help it. For example, sometimes all I have near me is a retractable pen, and I can't resist clicking it over and over and over...and over. Other times I mess with the desks/chairs around me, sliding my foot under the legs and moving them around. This is all while I'm sitting in the front row with a very bored look on my face. Naturally, the really boring teachers don't like me much.
I forgot doodling. In high school, I'd fill entire pages with doodles. Now I don't do that as much.
When I'm bored in class i draw. Sometimes i talk depending on who's in my class. Sometimes i read.
At the moment i have no classes, just exams, and i don't think I'd want do draw in those (excluding my textiles paper).
And then in September, i will be drawing anyway (art college) so...
I finished my education forever last week! *happy dance* But I was a doodler of epic proportions when things got slow - which was a lot. I used to go through phases of drawing the same doodle too. There was the sheep phase, the girls-with-big-ponytails-and-guns phase, the jigsaw puzzles, the squiggly flowers...
But sometimes I'd get bored of doodling, so I'd write some funny little stories instead. Just from last semester, in the margin of one page of notes I have the first chapter of an epic tale in which me and my best buddy make a daring escape from one particularly boring lecture, taking the rest of our study group with us. I need to finish that story one day.
Back when I still had my computers class, I would just switch over to anime. Teach didn't even seem to care, so after a while i would just get half way through my work and watch anime for the last 50 minutes of an hour and 10 minute class.
I have all my books full of pencil/pen manga sketches in the borders...XD
However I used reading manga or computer newspaper when I was bored..
I remember my Italian prof talking with my friends about guys and boyfriends and suddenly asking for my opinion, and me giving a "uh??!"as an answer. I was reading "Pc Magazine".
The only girl in the class who could use a pc. Sigh.
I still remember the amazed face made by a classmate when I setted the clock on her walkman...why the hell girls are usually so useless when there's technology to use?I feel like a monsteeeer... (guess I went a little OT,sorry)
either sleep, but in AP classes the teacher would wake you up and ask you more questions...
so then I just talked to friends or threw things around the room when she wasn't looking till someone got caught XD