SNG,
I thought about doing a similar experiment in which dice would be blindly thrown into an open box and the board would be asked the outcome. I may try it later tonight and see what happens...if I can find another willing participant.
You suggest that if genuine, a plethora of knowledge could be obtained from the board. Who's to say that, if there are spirits amongst us, they'll be helpful in any way? Humouring the possibility that they exist, perhaps their only intent is to entertain themselves. I'm not even sure if they'd be willing to participate in the dice experiment. I've been doing a lot of reading on spirit boards, and most "experts" say that you shouldn't ask trivial questions.
One thing that I haven't heard explained is if spirits ARE channeled through talking boards, why do we need to touch the planchette in order for it to move? If they're powerful enough to control my actions, or whatever they're supposed to be controlling, why not simply move the thing from letter to letter automatically?
REM,
Good points. I don't believe half the stuff I see on those paranormal programs (such as the orbs), but some of it has no explanation that I can think of.