This is an unofficial camera firmware that exposes a lot of manual options to most of the Powershot Canon cameras, including the Canon S95. The firmware gives you access to full manual control, Motion Detection, USB remote control, automation via scripting – and more!
In theory, the changes are not permanent and you can get your camera back to its original self if you want to. I have not tried it for myself, so I can’t vouch for that. Keep in mind that this is an “experimental” firmware and that you should be aware of the risks as there’s always a chance that your camera might be damaged permanently. Links: CHDK Wiki, Risks
In case you would like to extend the hardware as well, you can add a filter adapter kit to the front of the lens, from Lensmate and an ergonomic aluminum part that provides a better grip on the camera: Richard Franiec’s Custom S95/S90 Grip.
Thanks to Brian S. for the tip!