Grandmas have their grandkids more during vacations and having "busy stuff" is a great hint. I reuse a rubber banded check box containing "interesting busy toys." A freezer bag (stronger than a regular bag) works too. I have a wooden peg game, a small pencil & tablet, a small deck of cards, large colored dice which can be purchased in many gumball machines for about $0.25 each. For just a $1.25 you can get all 5 and keep everyone happy!
