Why are the teenage dog years, hopefully they are only a few months, but anyway, why are they called the "Kevin Stage" in the UK?  I've seen it here so often and never questionned before.  However I have recently misinformed someone that I thought it was called the Calvin stage so perhaps knowing why would help me remember the correct term.  :)  Just idle curiosity.

We had a comedy sketch show (I think in the 90s), which featured a revolting teenage boy called Kevin. He was moody and stroppy whenever his parents spoke to him. Ever since then people call it the Kevin stage.

Here's a link with more about Kevin...

http://en.wikipedia.org/wiki/Kevin_the_Teenager

Yep, this is the relevant bit:
In the first episode of Harry Enfield and Chums (the new name for the show), Kevin, now sans his older brother, reached his thirteenth birthday. The sketch showed his parents watching in horror as Kevin lost his sense of dress, courtesy and posture as the clock struck midnight on the day of his thirteenth birthday, thus becoming Kevin the Teenager, one of the most memorable of Harry Enfield's comic creations.

Kevin becomes a Teenager sketch.

Isn't it funny how things like "Kevin stage" become part of our language...with out us realising!
"Lovely Jubbly" ;-)

oh no bilbo if we go on like that I cant imagine where it would lead to lol

Great, thanks.  I saw the sketch.  Perfect analogy, right down to the seeming suddeness of the change in behaviour.  :)