So, something clearly ain't quite right.
atlas is really jittery. wget updates its status a billion times a second, calculating the rate incorrectly. gkrellm bursts ahead, lags behind, bursts ahead. mythtv and mplayer are totally useless. I saw the clock flicker down a minute and then back up.
I watched C-beams glitter in the dark near the Tannhauser gate.
I'm going to try switching from the gentoo-sources kernel (which I wasn't using before) to a vanilla 2.6.12.Update
: 2.6.12 fixed it. BIG SIGH OF RELIEF. Now I can go back to worrying about *regular* stability issues.