I've been familiar with multicolored hens' eggs since childhood. We always kept Araucana hens, partly because the eggs are so pretty and partly because they and their roosters are very mellow and non-aggressive. Their egg shells range in color from an almost olive green to lighter green to pale blue. The insides are the same as any other egg.
This photo shows a pretty good range of egg colors from my aunt's chickens:
It's a little difficult to tell because of the boiling water, but there are green, blue, pink, brown and white eggs in there. Fun, huh?
Part of me really wishes that I could build a chicken coop in my yard and keep hens for the eggs. However, it's not legal in the town where I live. Add to that the number and variety of predators that I regularly see roaming the yard and it would probably cause me more angst than it's worth anyway. I do enjoy farm fresh eggs, though.