This may sound horrible, but if there is some free time in school that you are able to use however you want, I would suggest socializing. I don't know what your time outside of school is like, but there is probably more than enough to allow you to roam your favorite forums outside of school. I can understand how boring school can be, having to go through learning things you are not interested in, massive amounts of time that could be used more effectively (at least in our minds). There is some knowledge that you will not need after you finish school, but I have found that I have used a lot more of that knowledge that I thought was useless after graduating.
I agree with Steve Jobs
here that technology, although great and useful, can be a dangerous tool for the younger generations. I also feel that somehow we need to teach these generations to appreciate the technology they have and to not abuse it. I want to make it clear that I am not accusing anyone of abusing technology. Instant gratification has become an important part of our lives which I feel is part of what will tear us down.
Sorry for the rambling, on topic, if you feel like you are being trolled, use the features that are built into the site that others have suggested, reporting and ignoring. They can be your best friends in situations like these.