Take a look here: http://chdk.wikia.com/wiki/Main_Page.
It's called CHDK firmware, and it's an open-source firmware you can put on most Canon Powershot camera's, including the G7. It's great! I get to do a lot of cool stuff now, like:
- Make RAW photo's
- Create scripts, for example for making time-lapse pictures (don't need my laptop anymore, yay!)
- Play Sokoban on my camera :D