I live in an apartment complex which uses a shared IP address for the entire complex (300+ individuals with one or more computers). In an effort to speed up my page access times (downloading works just fine...its the lookups that take forever) I decided to try using OpenDNS instead of the default DNS servers from the ISP. It worked spectacularly after I changed it and everything was working very fast until I decided to see how well Hulu would work. I went to hulu and lo and behold, someone had staked a claim on our IP address and left me a wonderful message stating "Remember who you are and that you are loved. -Mom & Dad". Clearly, someone's parents trying to keep their child on task at school (I live right next to a univeristy) and away from the more distracting or shady areas of the internet didn't realize that the IP address that they said their child was at is a shared IP and that they would be blocking sites for everyone. Is there anything I can do about this?

I had to switch my DNSs back and so I am back to slow lookup times, but I would really like to use OpenDNS. It doesn't seem right that someone can stake a claim to a shared IP when they aren't the owner and then people also using the shared IP can't do anything about it.

Beside what cindelicato said, I would like to encourage you to open a support ticket:
https://dashboard.opendns.com/support/

Provide them with the IP address as seen from:
nslookup myip.opendns.com. 208.67.222.222
and they may exempt this IP address (range) from being able to be registered with a network. This is bad for "Mom & Dad", but good for everyone else. "Mom & Dad" may find another solution, e.g. with their router features or local software.