Way to tell (will be) Great-Great Grandparents?!

SLWoody

My husband (26 years old) is very lucky - he has great grandparents which are still living and in very good health! They are ages 89 and 90. We are trying to come up with a really fun and creative way to tell them. For my husband's parents, we just bought a baby picture frame and a note inside that said "Coming Soon - October 2012". For his Grandparents, we put the sonogram in the very back of our wedding album (we got married in September) and they saw it when they flipped the last page.

 We are looking for ideas on how to tell the baby's Great Great Grandparents - please help!!