Since version 2 came out in 2005, Google Desktop for Windows has included a sidebar that users can fill with screen gadgets, but the Linux version (version 1, from June 2007) provided only indexing and search functions, with no eye candy whatsoever. This has finally changed. Google recently released Google Gadgets for Linux (GGL), which closes the gap between the operating systems. With GGL, you can run as many gadgets as you wish on your screen -- or at least that's the idea. Some flaws still need to be fixed, and not everything works 100% correctly.
GGL resembles SuperKaramba, Screenlets, gDesklets, and KDE 4's Plasma. All produce similar results and offer similar gadgets, and the only reason to choose one over another is if it offers unique gadgets you're particularly interested in. Some programs are compatible with each other, allowing you to run gadgets from other programs; there's even talk that Plasma will be able to run GGL gadgets directly.
License and installation
GGL is licensed under the Apache License 2.0. It is currently in version 0.10.0 and qualifies as "development" software, so expect bugs. If you happen to find some quirky behavior or errors, you can help by posting about your issues on the Google Groups user forum. GGL developers visit this forum, so you should get an answer and get the ball rolling to fix some of the remaining bugs.
Installing GGL can be difficult. If you're up for solving lots of dependencies by hand (by installing many packages), try getting the source code and following the building instructions to build it from scratch. However, be prepared to work a while over it. Debian, Fedora, Mandriva, and Ubuntu users might be in luck, as the project provides specific instructions for those distributions. I am mainly an openSUSE 10.3 user, but after fruitlessly trying to get all the needed packages (I still don't know why the build process claimed I was lacking certain libraries, which I'm sure I already had), I opted to "1-click install" an already built package provided by the openSUSE Build Service. At first I installed google-gadgets-qt (for KDE), but later I revised my decision and opted for google-gadgets-gtk (for GNOME); more on this in a moment.
Mandriva users can also get an already built package from contrib/backports. I tried that, but GGL wouldn't connect to the server and download any gadgets. Some searching on the Internet provided the solution: although it isn't required, you must have the curl and openssl packages installed. Also, be sure to have the Flash plugin for Firefox, or you won't be able to use many gadgets that depend on it. Finally, check that your /etc/X11/xorg.conf file includes the following lines, or gadgets won't have transparent backgrounds:
Linux.com :: Google Gadgets for Linux -- almost there