I have been trying to find a way to get important google videos onto my computer in AVI format for a while, and tonight I found the secret at the source link of reference for this little vanity. If you go to any video at Google Video, and look on the left side of page, you see a button called "Download" and then "for" with a pull down menu whose default is "Windows/Mac".
Click that button and the area below the button expands with options. At this point, depending on browser, etc, a download of Google Video Player may try to start. You can cancel that if you wish.
You will now see two new links below the button. One is to download video player, and the important one is "Manually download the video".
Click on that and a file will download, but it isn't the video. It is a text file that instructs Google Video Player on where to find the AVI file for that video. If you open the file you just download in Notepad or any other text editor, you will see the URL of the AVI file for the video.
It is a very very long URL, and I couldn't post an example here without screwing up this post, but it is fairly obvious when you see the text file.
Copy and paste the URL into your browser and you can download the AVI file and save it to your computer. Works like a charm!