I saw this somewhere (I can't remember where) and I thought this was such a good idea!
I punched holes in the corner of each card, and put them on a binder ring. (I don't know if that's what it's called, but you know what I mean.) I put all of Jackson's on one and Mia's on another. I think they'll enjoy looking through them when they're older. Now all of my cards are organized in my memory box.