I know there are plenty of grip strength exercises out there already but I happened to discover one by accident.
Disclaimer: If someone has already discovered this one, I apologize as I have never really done much research on grip strength training.
On each floor of my fraternity house we have water coolers. Generally when someone notices that the cooler is empty he'll go down to the bottom floor and get a new jug. Given that I'm not a lazy bastard I generally carry up 2 at a time. Well one night I decided that instead of throwing them up on my shoulder I'd just grab them around the top (or bottom, whatever, where the water comes out) and carry them up the two floors that way. Well by the time I got to my floor my forearms were on fire. Just so you know, they were 5gal jugs, so that works out to 40lbs per jug.
I realize that for some of you this might be light so you could always add some sand. If it's too heavy, obviously use less water.
But, using less water poses a possible problem. That being, if the jug isn't completely full, the water is going to splash around making it harder to control as you move. However, I see this as a good thing. As the water is splashing around, your grip will constantly have to adapt to the movement of the water. For those of you into martial arts, this might simulate an opponent trying to free himself from a grappling hold.
Just to clarify, what makes this exercise difficult is it's almost impossible for any of the weight to rest in the palm or on the fingers because the jug will probably be perpendicular to the ground if you are using enough weight.
Let me know what you guys think. Like I said, I just kind of stumbled on to this idea.