"The boys are eating some good bread."
Translation:Les garçons mangent du bon pain.
Basically, 90% of adjectives are placed after the noun, in French.
With this link, you will know more about exceptions: http://french.about.com/od/grammar/a/adjectives_4.htm
It has to do with literal vs. figurative. Figurative is before the noun and literal is after to help distinguish meaning. In this example, the bread is good, but it does not literally have a "good" trait like people do. Apples are literally red so rouge goes after pomme. It's easy once you understand the logic behind the placement of adjectives.