Long walks in the woods starting at 2ish.
Long baths on weekends.
Outdoors as much as possible. Minimum twice a day on weekends. (Lots of scientific evidence that it helps with focus for at least certain types of kids - green fields being best).
Depending on the season and his inclination we usually have some class going - gymnastic classes and swim classes seem to work the best so far. Most important part being timing (can't be too tired or too hungry), personality of the teacher, and whether the facility is calm (good) or overstimulating (not good).

Lots of heavy blankets (just plush king or queen sized from target). great for fort making or snuggling under. He loves the weight and texture of the blankets - very calming.

Two years of OT.

Family trips to some of the great MOCO county pools/splash parks are great.

Being outdoors is more calming than indoors - so we have appropriate gear for all kinds of weather.

We let him push the shopping cart; heavier the better.
I let him scrub the sink after meals.
He is responsible of closing all the (heavy) doors.
We have a bike and a scooter and a skateboard and a tramboline at home (consequently no dining table!); so he doesn't need outdoors for action.

How about a mini obstacle course or one of those tunnels you can crawl through? Yoga ball or balance board:

http://www.amazon.com/Reebok-05-55101-Balance-Board/dp/B003PAZ7B4/ref=cm_lmf_tit_9

My SPD DS constantly craves movement. We already have a trampoline and ask him to move boxes with toys, and do jumping jacks in the morning before he goes to school.

Do you have your own special tricks you would be willing to share? I am constantly looking for new ideas