Yankees to Screw In Light Bulb

Q: How many yankees does it take to screw in an lightbulb
A   None. Thats what rednecks are for.

Heavy Metal Fans to Change Lightbulb

Q: How many heavy metal fans does it take to change a light bulb?
A: Three. One to change it and two to say "Excelleeeeeent !"

Light Bulb - Chess Grandmasters

Q: How many chess grandmasters does it take to change a lightbulb?
A: 21. One to have the idea, and a whole load more to do all the analysis.