What are effective exercises for developing bicep muscles?

Good biceps

I've Been in the Marines for about a year now and I've found two good ways to get good biceps pull ups, and "21's" by 21's I mean do your curls by doing 7 half way up, 7 the rest of the way up and 7 all the way up
More input from FAQ Farmers:

• The first queston is, do you want good looking biceps or do yo want strong biceps. For the latter I agree with my fellow Devil Dog, curl and pullups will streghten it for sure. Try working with heavy weights and slow movements.

• To help with appearance, don't forget your tricep, a strong and well developed tricep will help push the bicep to the upper area of the arm for the classic bicep look most people are aiming for.

• I agree with both priors and will just add: try doing standing cable curls, it keeps constant tension on the muscle and is harder on the negative than free weights. Pull ups and such will make it thicker but concentrate curls will give you a taller peak and make it harder.

• Ok, try this out. (doing biceps 2x a week) 1 week do 3x8 standing db curls. Week 2, do 3x12 bi curls. Week 3 do 3x12 bi curls. And week 4, one day do 3x3, and one day do 3x5. Cycle this, meaning once you've finished the process start from the beginning again. This'll give you 3 weeks of mass reps, and 1 week of strength reps. Try and keep each 2 days apart, for example once on Mon, and once on Thurs.

*Chin ups directly affect the bicep more than pull ups; pull ups target your lats on your back.