Spending as much time with their grandparents as possible. I never had the opportunity. Both my grandfathers died the year I was born. One grandmother died when I was 16, but she lived in Florida and we didn't see her often. My other grandmother I knew the best. She was 89 when she died, but we only saw her a couple times a year.
Both sets of the grandparents live close and we visit ( or they visit ) as often as possible and the boys just adore them all!
I try to take as many pictures as possible so they will always have them to look back on. I asked each set of grandparents to write down memories of their childhood experiences and words of wisdom for both my boys so they can read it when they they are older.