My son is 12 now, and he has SPD issues. When I think about my son in school, and how they have cut back recess time so much in comparisson to when his brother (3yrs older) was in those grades, I know that since I am not hearing stuff from school, he is highly containing himself. When they get home - its their zone - to feel safe, to be themselves. Its like an explosion of pent up energy, physical, and mental. I have SPD as a 42yr old, and I can relate to how terrible it is, going into public, and keeping myself under wraps, about the senses that are assulted - just at the grocery store. Its a nightmare - Imagine what its like to be one of these little guys - who have no choice, or outlet, in school, and they cant articulate, what exact senses are being assulted yet, for how many hours??? How do I help my son? well - he has at least an hour, if not more, to be active as soon as he gets off the bus - he needs that time - to get it out. My other son, would come in, and I could make him do his homework, no problem. My husband expected me to do the same with the younger one - but I just knew that would never work. I have an extreme advantage because of my SPD, to understand him. Sports things are good to get the physical energy out for sure. My son will kick the soccerball around, or shoot some hoops, and I used to play catch with him. In the house, a wii active game - or games of catch can still be done with foam balls, or blow up one, even balloons are a great substitute. Im sure you get the idea. Of course, my son can also have more of mental build up too. So there are types of games that I let him zone out on for a certain amount of time - that brings him to a calm settled spot. Things that either have a calming repetition, or things that he must concentrate on - but wants to, and loves to do.
Main thing is - they need that period after keeping themselves under wraps, and home is their comforting, safe place. I am lucky to have the same issues as an adult, because I know what it feels like, and I have worse SPD than my son, for the last 4 years. We talk about it, and how things are, and I have tried to give him different sesory outlets, or safety zones in the home.
Just an idea for parents of kids with SPD, to check out - adult stories, since we are far more capable of expressing what different things, that seem so minor to others, are triggering us - since at 42, I had to pinpoint many of these things to start having a life again. Its far more complicated that just trying. There is a whole lot of strategizing. Outlets are key to these guys, I think.

I hope this helps a little - keep us posted! stacey