Looks like the DNS servers for their domain are not responding to queries. Domain registration is good till 2014. I'm guessing if you knew the IP the sites still up. There hosting service is having an issue.
NS1.CENTRALPROCESSINGUNIT.COM
NS2.CENTRALPROCESSINGUNIT.COM
I'm not familiar with CENTRALPROCESSINGUNIT.COM. But they seem to be the source of the problem. There servers don't seem to be doing anything. Googleing them show they're responsible for a handful of domain's DNS records. I'm guessing their all down.
XeNoSCR