[I'm not a physicist] I like your analogy for color entanglement. However, it doesn't show the "weirdness" of superposition (the balls don't have a concrete value until one of the boxes are opened, at which point, this triggers the determination of the open box's color value), nor the "spookiness" of action-at-a-distance (opening one box instantly influences the state of the ball in the other box -- which now must be the opposite color when its box is opened).

Intuitively, someone might think: well, the ball colors were "decided" while the two balls were next to each other (ballA will be orange, ballB will be purple), and the information about the color is attached to the balls, so the balls know what color to be when they are separated and later opened (they have "hidden variables" indicating the assigned color)....however, the reality (provable statistically by Bell's Theorem) is that the balls do not carry this color information, and instead the act of opening the box, randomly sets the color of BallA and instantly affects the color that BallB will have.

So if both people synchronize the time to open the box (that has some time relativity problems), so that BoxA is opened a fraction of a second before BoxB, then BoxA's color will influence BoxB's color (seen a fraction of a second later), but that will have happened faster than the speed of light would allow if BoxA was sharing its color information with BoxB.