LOADS of these (few megabytes):

2010-09-09 00:35:54: (mod_fastcgi.c.3356) response not received, request sent: 1109 on socket: unix:/var/run/lighttpd/php-fastcgi.socket-0 for /forum/index.php?, closing connection
2010-09-09 00:35:55: (mod_fastcgi.c.2568) unexpected end-of-file (perhaps the fastcgi process died): pid: 19346 socket: unix:/var/run/lighttpd/php-fastcgi.socket-0

all with the same url.

then a load of these:

2010-09-10 12:16:11: (server.c.1398) [note] sockets disabled, connection limit reached
2010-09-10 12:16:16: (server.c.1352) [note] sockets enabled again