A family quilt? For my DH's GM's 80th birthday, they asked for each part of the family to create a specifically-sized square using fabric paint, which was decorated to represent our "branch" and the names. Then they had someone piece it together.
For my GM's 80th, I did someting similar-- I had a number of crewel squares that her husband had done when he was bedridden from an illness -- I'd had them for nearly 15 years.
As my grandmothers aged, I also tried to get something to remind them of their growing-up years. For my other grandmother, I've done Ukrainian poetry books, certificates from Ellis Island (her parents both came through Ellis Island -- they have a great website and was even able to purchase a picture of the ship and its manifest). For Christmas this year, I made homemade Christmas bread, and Fedexed it for arrival on Christmas eve. Same grandmother grew up in Brooklyn, and I was able to find (through Dover) a picture book of the neighborhood during the years she lived there -- it was a great memory jogger.
Be creative, and good luck!