Here is an idea.
I would go out an buy nursery rhyme books one for each person. Attach to the front cover before you wrap, a message that says, "you might want to brush up on your nusery rhymes...." At dinner one night hand out the wrapped books to each person. And instruct everyone that they must all unwrap their books at the same time.
Then if you know what the s*x is, have Disney make a blue or pink cake covered in chocolate frosting so you can annouce weather its a boy or girl once you cut into the cake