Google has a fantastic little add on called Gears, unfortunately there is no support from Google to install Google Gears on your 64bit Linux machine. However, the good news is that Google was kind enough to provide Gears as open source! Users of Gmail, Wordpress, Greasemonkey and Wikipedia can greatly benefit from this little gem. Gears is a extension that allows you to take commonly used web applications off line. Storing essential components locally on your computer, making them as quick as can be. More on Google Gears can be found here.
There have been a few different people to release a 64bit compatible Gears add on, however some have issues and some don't. So far, I've found the best one to be written by a nice guy who calls himself Niels. Niels of Niels` blog has a link here on his blog.