To prevent a new thread each time we have any technical problems I thought I'd change the name of this one and we'll just keep it updated in the comments.
Sites back up at the moment, but if the track record for the rest of the day persists they'll go back down again in a few minutes. We're trying to find the source of the problem.
We're having intermittent server issues today with the CPU spinnign up and lockign the box. The suspect is OpenX 2.6.0 which we upgraded earlier in the week. Looking into it deeper now and hopefully have news soon.
OK, We've found the problem. And it wasn't OpenX (sorry dudes) it was Seesmic. Something went wonky with the plugin on our LA site and it was spinning out of control and bringing down the whole network. We axed it for the moment and all is back to normal. Looking into what happened and what to do from here now, but in the meantime all should be solid. Thanks for hanging in there.
Sean, sorry to hear the seesmic plugin was giving you trouble. When you get a chance, I would really appreciate you or Jason letting me know what you tracked the issue back to. I know you're running an older version of the plugin, but it still shouldn't be able to do that much damage.