I like to work early in the morning, and have been pretty annoyed when my relatively slow Asus eee seemingly randomly ground almost to a complete halt for a few minutes every morning. I noticed eventually that this happened around 7:30, and I usually had to kill some processes, such as these, to get work done:
/usr/bin/python /usr/sbin/update-apt-xapian-index --update --quiet
/usr/bin/find / -ignore_readdir_race ( -fstype NFS -o -fstype nfs -o -fstype nfs
It turns out that anacron was set up (presumably by default) to run all the daily cron jobs (defined in /etc/cron.daily) at 7:30.