Aside from the forearm work i do in the shower before work? :run:
Try this to FRY your forearms. Get yourself a bar about 2ft long. Tie a peice of 'strong' string or wire round it, long enough to reach the floor when you hold the bar at shoulder level.
To the other end tie a plate (try 10kg to start).
Now simply hold the bar with an over hand grip and rotate it to wind the string up, lifting the plate. When you reach the top 'slowly' unwind to lower the plate back to the floor.
To make it more difficult use a longer string and stand on a bench.
Great finisher after an arm workout!