Which'll teach you to get on the Internet at 7 a.m. on a Sunday, but in any case, the issue was a routing misconfiguration at Level 3, one of the larger Internet backbone providers (i.e., they provide the giant pipes that connect your Internet provider to Web sites' Internet providers).
A technical explanation from Pair Networks (UHub's Web hosting service):
Level3, one of our network providers, has been having a major intermittent outage affecting at least the East Coast of the United States since approximately 6:00 AM this morning. They are accepting traffic for our network and dropping 50% or more of it. Even when we shut down the line, they continue to announce and drop traffic (a situation reported by other network operators in a variety of locations as well). Until they correct their configuration issue and honor our requests to stop announcing our traffic, this problem will persist. We are keeping as much pressure on them as we can to resolve the issue. Anyone who reaches our network via any of our other network providers -- Telia, GTT, or Cogent -- will be unaffected.