I work in a datacenter and they block everything. I can't get to GR from work because they block all but the standard ports. They even throttle traffic for music streaming.
I get around it with SunVPN. It's OpenVPN based and I can connect to them through port 80. To the firewall it looks like regular web traffic but it's encrypted so they can't filter. With that connected I can bypass the firewall and do whatever I want.
There are a lot of OpenVPN providers out there. I can also connect with my iPhone and Galaxy S4 so they can't see what I'm doing.
Can you get to ANY website on their wifi?