The Tombuntu blog details how to install and get more from the recently-released Google Gadgets for Linux in Ubuntu or other Debian-based Linux distributions. The non-compilation instructions alone are worth a read, but the post points out a pretty nifty Compiz tweak that adds puts Gadgets on an OS X-like switchable screen. Make sure you've got the
compizconfig-settings-manager package installed in Ubuntu, and then:
Launch System->Preferences->Advanced Desktop Effects Settings. Enable the Widget Layer plugin, and enter its preferences screen. Select the Behaviour tab, and type the following into the Widget Windows text box:
You've now got gadgets hidden away until you press F9 (or another key you assign) to activate them.