Many of the other commenters don't seem to understand your issue (assuming I do). Yes, you can socialize a lot in high school and participate in other things. Most of these 'other things' turn out to be as fake as the 'education' the school provides. But that's even not the issue here. I would bet that, even with a lot of 'socializing', unless you lose your core thirst to learn (which would definitely be a bad thing), you would be left with an empty feeling and a bitter taste at the end of the day.
And no, "real life is boring too" is no more true that you make it to be. Most adults stick to the 'system' (just like most students don't think of how much high school is wasting their time and stick to it) and do not pursue what they truly enjoy. When your actual job (and its purpose) is something you truly enjoy, these 'mundane' tasks of dealing with accountants and such would not appear big to you at all - they'll just happen.
I felt the exact same way as you do in college (which is not very different from school where I live), and coped with it with some tactics. The first one was what charlesju's comment says:
"When I was in High School I used to pass the time by programming on my graphing calculator. I'm sure these days you can get by with reading a book in class or maybe even a small netbook. If none of those things are possible, just start a project and doodle your algorithms while you're in class and code them up at night.
There are a lot of ways to circumvent the system and do something you like to do, don't just give in to your immediate urges to shut it out. At the very least, you should graduate High School."
Some other comments here that I think would be useful to you:
"Treat high school as an experience, not as a place to go to learn- you've mastered the learning part (at least you better by getting rockstar grades), make a good effort to master the rest." - unexpected
"Stick with it, for now. It's not so much that it's a very valuable experience, it's that without it you will be locked out of so many other things that really are worthwhile. I know that two more years feels like an eternity right now, but trust me, it's not." - felixc
And a word of caution here, see if applies to you: http://news.ycombinator.com/item?id=583453 - tracy
Finally, whatever you do, get rid of this 'guilt' that you are doing something wrong. I myself was affected a lot by it, until at the end when we interviewed for jobs, I saw clearly that those who had gone with the system mostly failed, but those of us who tried to break out and learn ourselves faired exceedingly well. So be aware that you are part of an elite group and would be very welcome at the real world.
Unfortunately, many of the comments here too seem to reinforce that you are simply being immature, but your comment indicates to me you are not. In that case, be clear about this: some of us just can't bring ourselves to go along with the 'system'. Once you've seen how mind numbingly foolish it is, it is very difficult to stay there (I'm reminded of the film The Matrix). So, there's nothing wrong about that being difficult for you.
But realise that this difficulty is something you have to overcome. Simply dropping out will complicate many other things in life, so I would not recommend it. Instead, understand yourself, and find ways to work around the system and make it palatable to you. If you forget about what the classes are actually supposed to teach and instead think deeply about what is being taught, you'll find that every moment can teach you a lot. Same goes for any work you're assigned - simply overperform (according to your standards - the school may not consider it excellent performance, but you know to ignore it). Research deeply about any assignment you're given, and if you're unable to do that (due to say lack of time), brainstorm yourself while writing down (or typing out) about the concept there. If you do this sincerely, you'll find that you enjoy the process, while excellent grades come your way without even all the 'hard work' the 'sincere' students put in.
To summarize the idea - you're interested in learning a lot, so use the things you do at school to do it; when you do the school work with concentration and dedication, you'll find that you've learnt a lot more than the teacher meant you to, while enjoying every moment of it.