Conky is a free, light-weight system monitor for X, that displays any kind of information on your desktop.
License: Open Source
Screenlets is both a Python framework to simplify writing Cairo-drawn desktop widgets, similar to those found in the "Dashboard" feature of OSX, and a collection of widgets written using the framework. It is designed to work with any modern Linux desktop. Developed by Rico Pfaus, Helder Fraga, Natan Yellin
License: Open Source
Conky is a highly customizable and lightweight system monitor that requires manual configuration, making it suitable for advanced users who want detailed monitoring. In contrast, Screenlets offers a more user-friendly experience with pre-made widgets, but it lacks the extensive customization options and features of Conky.