Probably your Web server OOMing the box? Check dmesg.
Apache-specific advice: if you're on a small VPS or other box with not much RAM, and didn't tweak the distribution defaults for MaxClients and friends in its configuration, a HN-size load will OOM you rapidly, especially with mod_php. The defaults for prefork MPM are nuts in the major distros (as in, assuming 4 GB of RAM or more for mod_php).
Since you're going up and down, I assume this is the case. I suggest dropping MaxClients to 5 for now and letting us wait a bit.
Yeah, i thought i had it back up, went in to a meeting, came back and it's down. When i went in and looked at it there were a ton of apache2 processes. It's my blog server, so i don't pay a lot of attention to it, i probably should.
I dropped down the number of preforked apache processes, we'll see if that helps. It's also where i run some rails experiments, so we'll see. Load's back up to 7...
