I was a Mediacom subscriber for years and recently switched to Centurylink which is just as bad, if not worse on 404 redirects. The solution, changing DNS servers. Many options are available here and some even offer filtering for sites that are know to host viruses and even pron. A great little benchmarking utility is available at http://www.grc.com/dns/benchmark.htm that can offer many options and show you just how crappy your ISP's DNS server can be.
My kids use Edubuntu with a limited user account and the Kidzui add-on for Firefox... They love it!
I actually installed Edubuntu on top of vanilla Ubuntu, for some reason it seemed to work better that way.
At some point, I am going to install an ipcop server to control the traffic a little better, but I am in no hurry.