Graphical notification of reboot/power cycle

Never silently reboot/halt the machine; provide a graphical notification that the system is due for a power cycle with uptime remaining:

On RedHat systems at our university installation, the xconsole application pops up a GUI notification when the system is due to be rebooted or shut down.

On Ubuntu, there is no GUI notification. The machine just reboots while the user is in the middle of their work, without any notification that there will be a reboot! The exception is if the user has a tty open, in which case they will get the message:

Broadcast message from root@rover (pts/11) (Mon May 8 21:23:22 2006):

The system is going DOWN for reboot in 10 minutes!

Unfortunately, most users today don't keep an X terminal running these days, so such notifications should reach the user, perhaps via notification-daemon. An alternative might be to have some kind of egg-timer along the lines of the battery applet, but this might be too invasive/overengineering for the dapper release.