8. Turning the Caber
The caber is basically a log that athletes attempt to flip end-over-end. The caber is judged by the straightness of the turn by the head judge, who follows behind the athlete to get the best view. The event is sometimes referred to as the caber toss, but this is incorrect because the caber is not tossed; it is not heaved over a bar.
There are a lot of myths about how caber tossing originated, but my opinion is that it's just a neat way to propell a log through the air. It's just interesting to have a contest with a log, and see who can flip it over. That's probably how it started, and that's how it is today. I don't see any need to make up a story about how it was used in warfare to scale a castle wall or in logging.
A perfect execution is called a "twelve o-clock turn," where the caber falls straight away from where the athlete released it. The terminology derives from the release point being at the "6" and the caber planting at the center of an imaginary clock face. Then the caber becomes the hour hand upon landing. In a 12-o-clock toss, the caber falls away from the thrower, and the caber forms a straight line through the thrower. Sometimes the caber falls off slightly to the side. This may be a 10-o-clock, or 11:30, etc. Note that in scoring, a 10:00 is equivalent to a 2:00.
If the athlete fails to turn the caber (the caber does not land between 9 and 3 o'clock), the side judge estimates the maximum angle that the caber achieved from vertical (from 0 to 90 degrees).

DESCRIPTIONS FROM OTHER SITES
Celtic/Scottish Festival Primer by Clan MacLachlan.