Gender Reveal Ideas for Great-Grandmother??

Just found out we are having a little girl! We are waiting until my grandmother's 70th birthday party we are throwing her to announce it to everyone. Any ideas on some cool ways to do it? This will be her first great-granddaughter! Her first great grandchild was our son so this makes one of each for her now. I was thinking of presenting it as the last gift to her in a regular box that will have some pink booties in it. Any other suggestions?