One of the wonderful things we got tipped off to when Mad Natter first started showing his sensory issues was the concept of a Bean Box. This turned out to be one of the best things ever. Not only was it less messy than a cookie tray full of shaving cream, and more interesting than playing with sandpaper, but it was something to explore, which seems to have made all the difference.
I grabbed a box from the dollar store, basically just the size of a sheet of paper. I emptied a bag of black-eyed peas and another of lentils into the box, and put in several handfuls of dollar store toys - light up rings, plastic dinosaurs, some rubber worms, things like that. You wouldn't think this would be a long term activity, mostly because there aren't a lot of toys in there, and it's not really a large scale toy of any kind.
This past weekend, though, Mad Natter asked to pull the bean box down. He hadn't played with it in a while, so I figured he'd play for a little while, and I could get lunch on the table. Apparently, I underestimated the amusement value of the bean box. He spent the rest of the afternoon, and on into the evening, playing with the beans and the toys. He made up games, he sifted the beans through his fingers, it was a long, quiet playtime. And, surprisingly, the box only spilled once (and Mad Natter had help knocking that over). It was a lovely, quiet, peaceful afternoon, and one I'm looking forward to seeing if we can repeat.