I'm going to surprise my son on his 25th birthday.?

I am flying to PA to surprise him. My question is what can I buy for his wife, who is going to be 22 this month also. I've never met her, and I don't know what she likes, since I am surprising my son and her too, I don't have anyone to ask except Yahoo experts like you. I am also going to meet my new granddaughter. ( I know what to get her!) Help!