Concentration Curls is a great exercise if you want huge biceps, according to studies Concentration Curls yield more biceps activity than barbell, cable or preacher curls.
Since the upper arm is stabilized against the back of the thigh, it isolates the biceps muscle.
All you need are Dummbells and a bench or chair to sit on.
How to do
Sit at an exercise bench or a low chair.
Position your feet flat on the floor and spread your knees somewhat to form a "V" with your legs.
Grab your weight in your right hand, put your elbow on the inside part of your right thigh or knee.
Curl the weight upward. When the weight is hanging bent below you, squeeze with your bicep to lift the weight back up towards you. Keep your upper arm and shoulder stationary while you do this.
Slowly lower the weight down. When you've raised the weight as far as it will go (it should be near your chest or torso at this point), slowly and gradually lower it back towards the floor.