What is the difference between a kayak and a canoe?

This actually came up on a pub quiz this week (the answer given was wrong!) A canoe has an open deck and the rowing position can be seated or kneeling and the oar used is usually single bladed - think native Americans in USA in 18th century or fur trappers in Canada. A great example of a canoe can bee seen paddled by Daniel Day Lewis in the 1992 film "The Last of the Mohicans". A kayak is a closed deck boat used in a seating position only and usually uses a double-bladed paddle, and usually comes with a spray skirt which enables you to perform an Eskimo roll (now sometimes called a kayak roll) - think Olympic slalom "rowing" down through whitewater rapids. The pub quiz question asked "In what vessel would you perform an Eskimo roll?" and gave "Canoe" as the answer - there was an immediate uproar from pretty much every team, and the question asker (who had not set the question) ended up allowing points to everyone with kayak or canoe as an answer.