Thanks for the great ideas for parent involvement! I will definitely introduce WBT at back to school night next year -- maybe I can record my current class and use that.
To answer your question, the "Because Slapper" is one of the new Brain Toys I learned at the Phoenix conference. Students lightly slap (or just place) one palm on the top of their other hand when they say because. I taught it to my students by telling them that when you say "because," you are piling sentences and ideas on top of one another. It's a way for them to use reasoning, evidence, evaluation -- all that great higher level thinking!
So for example, we have been working hard on distinguishing fact and opinion. If we read a passage, students could say, "This is a fact *because* (use the gesture) we could look this up in the encyclopedia and prove it." Or, "This is an opinion *because* (use the gesture) it's what one person thinks or believes." The best part is when students use it on their own. I almost cried when students started saying, "I know that David thinks basketball is the best sport, but my opinion is that soccer is the best sport *because* blah blah blah." (I can't remember, but one student gave 3 reasons to support her opinion...it was a great moment, not least because my students were being respectful of each other!)
Also try it with multiple choice math questions! Just like we practice the wrong way to do something in WBT, it's great to say why something is NOT the answer. It's good review and helps with retention.
I also use the Because Slapper for their writing. I will ask them to include "because" in a sentence, so you add written expression to the list of benefits.