To download YouTube Videos without any third party programs or extensions in Google Chrome, simply create a bookmark by pressing 'Ctrl+B' to bring up the Bookmark bar. In the 'Name' field, type in any name you want. In the 'URL' field, copy the following code:
Now, after you watch any YouTube video, you can click on the new bookmark and the video will be saved to your hard drive. Note: You may need to add .flv to the end of the File name in the Save dialog box for it to save correctly.