Stupid server
Looks like it was down much of last night. It hung again on me late last night, so I pulled out the two 128mb DIMMs and went to bed.
When I got up this morning, it was hung, so I put those DIMMs back in (the more RAM the merrier) and changed the network card.
I'm suspicious of the network card since it seems that network activity makes the problem happen faster. Of course more network activity usually means more bus activity, more disk activity.. so I could really be anything. I've run out of components to replace, so if it keeps happening I'll have to see about moving the database and web server onto another box...