What's Your Type?:
Since everyone with a computer is a graphic designer by default, we might as well know the terminology. Have your kids look through magazines at the type in headlines, comparing how the X-height changes from face to face. Then discuss the subjective differences between the various X-heights; is one more pleasing than another? (X-height is the height of the lower case "x" compared to a capital "X" of the same typestyle.)