I agree, pictures are a great suggestion
I kicked my own ass putting together albums last year. I worked really hard correcting and enhancing old black and white photos. It was a bitch, but totally worth it especially getting them on a disc, then the whole family can have copies.
Another suggestion for the grandparents are cozy clothes: slippers, robes, soft drawstring pants, anything warm, it's all about being comfortable at their age.
They also might like some Sinatra or Neal Diamond