Deactivate xscreensaver via SSH

While configuring my HTPC via SSH, I needed to deactivate its screensaver without having access to its own keyboard or mouse. Here's how to do that from the (SSH) command line:

xscreensaver-command -deactivate

If you happen to use gnome-screensaver (default in Ubuntu), the following command might help (not tested):

DISPLAY=:0 gnome-screensaver-command -p

Thanks to YaronSh on the Ubuntu forums.