Michael McCracken has another neat Growl trick for those of you with a Mac:

I have a few projects that take a long time to build. (C++ mostly, with many nested makefiles.) Since I’m guaranteed to go check email while it’s building and forget about it, I have gotten in the habit of using this incantation to have Growl tell me I should get back to work:

  gmake; echo "Returned status: " $? | growlnotify "Build done"

This gives me a notification titled "Build done" with the exit status from the shell variable $?, the status of the last performed shell command.

Then he goes on to show you how to plot build times with gnuplot. Nice! Free tools, priceless feedback.

(Growl is good stuff for monitoring things right from the comfort of your desktop. For example, I use it regularly as a tattletale for web sites.)