It seems I am running this bug. Sometimes my clock applet just stops running, and I have a pop-up window saying 'The clock has quit unexpectedly'. Between 'Reload' and 'Close', I have unfortunately chosen the second option. Even if I have rebooted, I cannot launch the applet anymore. I am on Ubuntu 10.10.
Can somebody give me the command line that I could use in the application launcher appearing when Alt + F2 are hit ? Or any other solution in order to recover the applet on the gnome-panel ?