If you enabled the gnome3-team ppa for Raring, you'll notice that your laptop won't suspend anymore when you close the lid. That is because that functionality has moved from gnome-settings-daemon into systemd, and the latter is not supported in Ubuntu.
A workaround is to install a hook to the acpi event yourself: save the
following file as /etc/acpi/local/lid.sh.post (update: create the
directory if it doesn't exist) and set its executable bit
(chmod u+x /etc/acpi/local/lid.sh.post):
#!/bin/bash
grep -q closed /proc/acpi/button/lid/*/state
if [ $? = 0 ]; then
pm-suspend
fi