It's very common for Wikipedia to be blocked, whether by a government or ISP. The great news is that all you need to do in order to unblock Wikipedia is to get a VPN account. Even if Wikipedia has been blocked, you will have instant access to Wikipedia one again.
In fact a VPN account will not only unblock Wikipedia, but all other websites and other programs such as VOIP/Skype that you may need to access.
If you need to unblock Wikipedia, a VPN account is your best value since it unblocks not only Wikipedia but everything else.