Attack this stubborn muscle to add some serious size to your lower legs.
1. For a period of 2-4 weeks,train your calves on a daily basis before returning to your normal program. Use about 4-6 sets per workout, doing a different exercise each day.
2. Every night before you go to bed, do a set of 100 slow, hard-squeezing standing calf raises with just your bodyweight on top of your normal program. Go for maximum burn!
3. Wherever possible, walk around on your tiptoes rather than your flat feet. Ballet dancers often have awesome calves.
4. Every time you encounter a staircase, do a calf raise up each step. On the way down, step onto the ball of your foot, as this will act almost like a plyometric movement for your calves.
5. Try doing two calves workouts per week: one with very heavy weights for sets of 4-6 reps, and one with very light weights for sets of 25-50 reps. This will attack fibers that you probably haven't been hitting with conventional workouts.
6. Do as Arnold did, and train calves in your bare feet (if your feet can handle it). This will increase the range of motion for any calf movement, and will force a very intense contraction.
Don't use all of these methods at once, or your calves could end up over-trained, which won't contribute to growth. Pick two or three items from the above list, and change things up every few weeks.