I was reading an article by strength coach John Davies (Renegade Training). He described an exercise that I have not seen done in the gym before; a one-arm barbell curl. I tried this one myself and was pleasantly surprised. It gives you a very strong contraction in the biceps and forearm flexors. I believe this is due to having to stabilize the long barbell. It is performed like one-arm db curls. Just make sure to grasp the barbell in the middle. Let me know how you guys liked it.