We do a lift at school called the road to hell. Take a straight bar with some amount of weight where you can curl it ten time with little problem, then quickly take 10 lbs off the bar and curl that 15 times, then do the same, drop 10 more lbs, and curl that 20 time. Once you have done this take dumbells of the same weight as your last curl set and do 20 curls each arm. That = 1 set try it for 2 or 3 sets.

Its a hell of a work out