Q. What is the difference between Mechanical Engineers and Civil Engineers? 
A. Mechanical Engineers build weapons, Civil Engineers build targets
Q. How many chemical engineers does it take to screw in a light bulb?
A. Just one. I hold on to the light bulb and the world revolves around me!
Q. When talking to an engineer, how can you tell an extroverted one from an introverted one?
A. An extroverted engineer will look at your shoes rather than their own when talking to you!