I walked down the hallway last weekend, probably in my usual "hurry" mode, and slipped and almost fell.  The floor was covered in sand.  Sand?  I don't have anything "sandy" in the house??  I had sand in almost every room.  

As I was sweeping the entire house, I ran across this poor deflated toy....Roomba seems to have found one of AJ's old lizards toys and carried it around for a while, losing sand the whole time.  Mystery solved!