There is a community that has been taking apart canon firmware and adding extra features to cameras. So far they are mainly doing this on point and shoot cameras. So if you have an old IXUS you might want to try it: although it's probably not for the faint of heart. Loading the new firmware gives a number of features to your point and shoot that weren't there before such as:
- Greater control over the shutter and ISO
- Providing RAW if it wasn't there before.
- Live histogram, visual indication of over/underexposed areas (Zebra mode)
- Higher compression on video so you can fit more minutes on your disk.
- Allow the USB port to be used to remote trigger the camera.
- See battery meter always
- Games and applications.
- Run an in camera programming language to do things like timelapse. (upload scripts)
There has been talk recently about building similar firmware for canon's digital firmware. This is a long way off. Someone has done a technology demonstration of the 40D recording video straight to the card (rather than needing a cable).
Still if you want to get more out of your point and shoot it might be of interest.
It's called the Canon Hacker Development Kit, and probably requires you to be brave with the warranty.