Sherman's aquarium is a screen saver, a GNOME panel applet, and a dock applet that provides an aquarium with fish and/or turtles. In applet mode, it can display lots of information, such as CPU load, temperatures, memory usage, and many other things. Both the applet and the screensaver are very configurable.
ChBg is for changing desktop backgrounds in a given period. It can render images with 10 modes (such as tiled, centered, scaled, etc.). It uses Imlib1, Imlib2, or gdk_pixbuf for loading images, so it supports many image formats. ChBg has a windowed setup program, is able to load setup files, can be used as slideshow picture previewer in its own window or as a desktop background, and can be used as screensaver or as an xscreensaver hack. It has a dialog for fast previewing of pictures and very usable thumbnail previews.