I think teachers go to their weekly meetings not to discuss important  things, but to share their new ways of reading students' expressions and  movements. Why do they always call on us when we don't know the answer  to a question and when we finally do know an answer, we're never called  on? Here are some ways to attempt to avoid being called on, some of  which I'm sure the smaller half of you have already tried.
ONE) Pretending to write notes.
That  moment you hear the teacher ask a question, stop doodling stick figures  with swords battling each other, and actually start copying down whatsoever on the overhead projector word. for. word. Try really hard to  look absorbed in these notes when, in actuality, you really have no  idea what you're copying down.
TWO) Avoiding eye contact with the teacher.
"Maybe if I don't look, s/he won't call on me."  This tactic fails the majority of the time, but you can still attempt  to succeed from time to time. This way varies from hiding behind your  hair (if you have long hair), to resting your head on your hands with  your head tilted opposite the teacher. If you're not comfortable still  sitting in your seat, you can also get up to sharpen your pencil.
THREE) Staring back at the teacher.
Return  the stare back at the teacher with a smirk as if you know the answer.  This can go both ways, if the teacher likes you, they'll more than  likely call on you. So depending on which class you have, choose your  ways wisely.
FOUR) OOPS. I dropped my pencil.
"Accidentally"  dropping your pen or pencil so you can take your time looking for it  until the teacher calls someone else. Make sure you fling it far from  where you sit so you have to get out of your seat to retrieve it.
And finally,
 
FIVE) Actually leaving the classroom. 
This  is the last resort. If you really have no idea what is going on in  class and you're extremely desperate, pretend you have a phone call or  have to use the restroom. Quietly rush out of the room as if you're in a  hurry, the teacher won't be able to call on you.
Now, these tactics I have suggested do not always work, if you still get called on, don't say I didn't warn you.