CHDK and SX40

Well, here:

http://images3.wikia.nocookie.net/__cb20120105020429/chdk/images/6/62/CHDK_User_Quick_Start_Guide.pdf

First, main thing, it works. What you use will depend on native features of the camera you own. In my case, most often used are RAW/DNG conversion, battery icon, zebra exposure indicator, long exposures (up to 64 sec), extra brackets for HDR. On my old S5IS the wonderful manual focus adjustment via zoom rocker (not on SX40). Now and then play with motion detection script.