Also, on the Exit on left or exit on right (http://media.tumblr.com/tumblr_mbyisdluoz1qhkzpz.jpg) - I don't think that applies to all cities. I know for a fact there is some signs in my city that do not do this, especially older signs.
The spoon breaks the surface tension of the bubbles, causing them to pop when they start to boil over.
Other people seem to be saying a metal spoon should work just as well (with the added bonus that it won't warp, unlike a wooden spoon), with the only downside that it will be hot to take off. I'm doubtful that a metal spoon would work as well though, because metal does not absorb moisture like wood and also has a smoother surface (i.e. less surface area on a microscopic level), and so it probably wouldn't be as effective in making the bubbles attach and pop. Of course the only way to know for sure would be to do an experiment.
I'm no chemist, but my observations from cooking and homebrewing, pasta and wort boil over worse than plain water because dissolved starches/sugars/proteins allow the bubbles to have greater surface tension and hold together better. If you cook with more water but the same quantity of food, the bubbles have less surface tension and you can probably avoid the boil over scenario altogether.
For this particular life tip, I would expect a starch-laden foam from cooking pasta to leave a residue on the spoon as the bubbles popped that would eventually let it boil over still. It will buy you some additional time before a mess is made of your stove though.