Episodes?

My 10 year-old son is, for the most part, a regular boy. However, a couple of times a day he will have "episodes" where he will be extremely silly, roughhouse a lot, and be unresponsive/oblivious to directions from parents/teachers. These usually last about 1/2 an hour or so. The event triggering the end of an episode is usually him getting hurt somehow or being sent to his room for a time-out (even that doesn't always stop it). My wife and I can't seem to head these off before they happen and we definitely can't stop an episode once it has started. Does anyone have any ideas?

By the way, he is not diagnosed or medicated. We are trying to avoid that as much as possible if we can.

I'm not really sure to be honest. It could by ADHD but you might want to try changing his diet and daily activity. Make sure he plays outside everyday (and burns some energy) and make sure he isn't getting too much sugar and fatty food.