conky - A light-weight system monitor for X
 
Conky is a system monitor for X originally based on the torsmo code.
Since it's original conception, Conky has changed a fair bit from
it's predecessor.  Conky can display just about anything, either on
your root desktop or in it's own window.  Conky has  many  built-in
objects, as well as the ability to execute programs and scripts, then
display the output from stdout.