Wolfram Research
Wolfram Math World: Real Part
This MathWorld site contains a graphical example of the real part of a complex number.
National Council of Teachers of Mathematics
Nctm: Figure This: How Many Colors of States Are on a Us Map
Try this data collection and analysis math challenge on map coloring. An interesting approach to analyzing complex data. This one page activity is part of the NCTM Math Challenges for Families collection.