Try 21 guns for a full arm workout. Just your basic bicep curl with a bar - 7 reps at 180 degrees, 7 reps where you bring the bar up all the way but only bring it down to 90 degrees, and then your last 7 reps are just like wrist curls. But I gaurantee those last 7 you'll feel right in your forearms!
Oh yeah, I tried that once. Left my arms sore for a week. lol.
But thanks, I forgot about that. And thanks to everyone else. I think I'm going to use pegonecity's workout and a heavy grip, which I actually own - just gotta look for it, lol.