Light Bulb - Canadians

Q: How many Canadians does it take to change a lightbulb?
A: Four. One to spray green paint onto the bulb so noone bashes it with a big stick, one to change it, one to suggest they all roll a log down a hill to celebrate, and one to invite all the others round to his log cabin so they can all watch his moose moult.

Light Bulb - USENETers

Q: How many USENETers does it take to screw in a light bulb?
A: None. They are so busy hogging up bandwidth taking out their postadolescent frustrations on each other, that they never get around to it!

Russian Leaders

Q: How many Russian leaders does it take to change a light bulb?
A: Nobody knows. Russian leaders don't last as long as light bulbs.