1. Child draws around Grandparent's hand. Then places her own hand in outline of Grandparent's hand and child and Grandparent together trace child's hand. This idea can be used to make a refrigerator drawing, a framed keepsake, a placemat, etc.
2. Another idea is to make grandparent's handprint with red or yellow fingerpaint.  After it dries, overlap child's handprint using blue or green fingerpaint.
3. Or both hands can be cast in 3/4" deep plaster, side by side.
4. Or handprints can be traced then embroidered.  (This is an opportunity for grandparent to teach grandchild how to embroider.)
5. Craft stores also have fabric paints which could be used to outline the handprints on T-shirts for grandchild and grandparent.

Me and My Gran - Hand in Hand!