Mysterious creatures those beavers.
I know nothing about this, so take it for what it's worth, but I'm gonna +1 the idea of just physically wearing him out. Kids have a LOT of energy and it has to go somewhere. If they don't have enough acceptable outlets, then it can come out in unacceptable ways. Not to say that there isn't a mental component, nor mental stimulation that could be helpful, but if you're just dog tired, it's harder to work up the will to be a terror.
In addition to all the good advice you've received, one thing that jumped out based on your description is that your son's love language is touch (affection). Here's the 5 love languages book for children: http://www.amazon.com/gp/product/B006YYUO98/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B006YYUO98&linkCode=as2&tag=kevnetchrcu00-20&linkId=T2XX6PKUBR5WIDUK
It's not the complete answer, but I know that understanding and identifying my children's love language has made parenting much easier (especially when their language is different from my own).
Another thing I've noticed is our boys go from Bruce Banner to the Hulk when they're hungry. They don't necessarily tell you they're hungry, but you'll pick up on it quickly. It's obvious enough that we've warned their teachers at the beginning of the school year.
You'll need to log in to post.