(Baby) Photo display
A great way to celebrate a baptism or baby dedication is to ask everyone to bring in a photo (if they have one) of their own baptism for show-and-tell! Maybe they even have the outfit they wore that day.
This is also a great way to talk with folks about the different traditions around baptism as some folks might have photos from an infant baptism or an adult baptism.
For a baby dedication you could bring in a baby photo!
To protect the photos, show them off using a photo clothesline.