For the starters here is a way, "proxies"
These are websites which acts as a tunnel through which you can browse yet other sites.
There are numerous proxies out there, If you want to try the ones not mentioned below well they are a Google search away.
These are two of the proxies i have had tried -
www.cooltunnel.com
www.hidemyass.com
for more Google is your best friend ;)
There are yet few more ways to brows blocked sites but i ll be skipping to the coolest one.
Now in some places these proxies too are blocked, how do you browse these sites now?
worry not there's a way.
this is called TOR. its a browser which encrypts (kind of locking or hiding for the less technical ones) your connections and makes it looks as if you are browsing from some other place other that where you are to someone who is using tor and whose in in some far away place. so the more of us use tor the more less likely it is to be safe. Actually this browser was build by some highly secretive government organizations for their connection to be safe (from hackers off-course) and this browser is not only used for browsing blocked sites, its used more by people for there anonymity across the web. well enough of history now let me get to the point, so tor.... yeah you can download it from www.tor.com and if its blocked, well once you are on your vacation at home you could download it, and for those more curious you could use other connections that is not blocked, may be connect to the internet on your computer through your mobile and download it or cafe could be even easy. and once you have got it you don't even need to install it just run it and browse whatever... yes i said what ever you want. And ah yeah blocked porn sites too can be accessed. Having that said you will not be able to browse Facebook with tor since Facebook is a pain in the ass. It track your web activity so it wont let you browse through tor. And for educational purpose using of Facebook is not a good idea. well if you want more on why i am telling you this you could ask me to post another page about it and i would be more that happy to tell you why. tell me how it did or did not help you in the comments below also any problems you faced will be clarified as long as they land on the comments. And if you want me to post on something you could always ask heck request in the comment below. ;)
P.s. if you want more to how tor works you could read it on tor's official site mentioned above and you could always ask in the comments. happy browsing :)