Through CHDK , Your Canon Camera will go Open Source. to unleash the power in those Canon that the manufacture did not want you to know about.
CHDK is a firmware enhancement that operates on a number of Canon Cameras. CHDK gets loaded into your camera's memory upon bootup (either manually or automatically). It provides additional functionality beyond that currently provided by the native camera firmware.
CHDK is not a permanent firmware upgrade: you decide how it is loaded (manually or automatically) and you can always easily remove it.
CHDK site is h3r3