At school, you are forever being told what to do. Parents tell you to attend, the teachers tell you what to learn, what to eat, what to wear, who to be friends with (and who not to)... the list goes on. It's almost like you're considered to be a prisoner or something like that. You'd expect that after coercing you to go there and all that stuff, they'd at the very least allow you to browse whichever sites you need as long as you are imprisoned there. Alas, that isn't the case. The internets are censored, and lots web sites are being blocked. As luck would have it, there are a couple of ways of going around the restrictions at least, and it's a lot more easy than getting your parents to homeschool you.
An unblocker is a kind of gateway that sit between the computer you're on and the site you're visiting. The unblocker accesses the site on your behalf, accesses the page, and sends it off to you. So the site you want to access only sees the unblocker's IP. So in effect you are surfing sites indirectly. Internet filters only see you accessing the unblocker, not the destination site.
Another way of unblocking Facebook in school is to set up your own unblocker tool. This is more advanced than just using an unblocker but better in the long run because if they block it, you can make another. How to do this is not in this guide, if you do a search for "How to make your own proxy" you should find instructions. You can even earn money from this by letting people advertise on it.
Other ways to get on Facebook are to use translator sites, for example Google Translate or Babelfish. Also try using Google's cache version of the site. Although, it won't let you to login that way, so you're better off using an unblocker for Facebook, however these tricks are good for most other sites.