Yikes Grandma's a Teenager - Zack Files Author:Dan Greenburg A trip to New York City to celebrate her 89th birthday--and participate in a Rockettes reunion at Radio City Music Hall--leaves Zack's Grandma Leah feeling younger than springtime. And she's looking that way too, since a strange trip through an airport metal detector turned back the hands of time and is making Grandma grow younger and younger!