Check Joshua Davis' page out. Great videos and a nice DIY link. He also appears to be a Linux user ;)
DAVIS
Hand Wrist Grip and Forearm Strength Training. Using Ironmind Captains of Crush Grippers , blobs and home made stuff. This BLOG is the rantings of a lunatic. His writings are opinion. Read at your own peril. But you will find some good training info. No fictional hand bullshit here. This is not a "grip parody" site. No Quarter Given. A Fucking Blob is a Fucking Blob - except for York "Legacy's" ;) Fuck Baraban.