CHDK is an exciting firmware extension for Canon cameras (GPL licensed). Using this extension you can give your camera the power of longer or faster exposure times (for example 60 seconds exposure instead of the 15 seconds limit). The same goes for aperture levels. You can also run personal scripts to capture a photo every few number of seconds to create a video-like photo-set, and more.
The thing is, the Canon G11 is one of the most feature-rich cameras in the market, so it needs this extension less than other cameras.
This was one of the reason CHDK was not released for Canon PowerShot G10. In fact, there is a CHDK for Canon G9, which means there can also be a CHDK for Canon G11.
If you have experience with Assembly or C programming, you may be able to help getting CHDK to the Canon G11 as well. Check out the links.
CHDK for Canon PowerShot G11 – Your help is required
CHDK Information For Developers
How-To: Expand your camera with CHDK (Hack-a-Day)

G11 Port of CHDK is allmost done:
http://chdk.setepontos.com/index.php/topic,4647.0.html
Excellent news!
Please update again when it’s finished. I’m going to give it a try
CHDK For Canon G11 Is Out! First Impressions
http://canong11.amirw.net/chdk-for-canon-g11-is-out-first-impressions/
I just got a G11 and am interested in your current (Nov 2010) opinion of using CHDK with the G11?