I remember plaid stamps- they may have been the ones to come from A&P. As a kid, I'd always heard of green stamps, but there wasn't a supermarket in my area that gave those. But the plaid stamps were the same sort of deal- I used to love helping to paste them in the books!
Cathy
P.S. I should add, I have really enjoyed reading everyone's reports of the Fest! Thanks very much!!