During the part of the Passover Seder when the 10 plagues are recited, there are a few customs done.
A sign of remembering each plague is when the plague is recited, taking your pinky finger and dipping it into the wine and dripping it onto your plate. By taking some wine out, represents never forgetting the Exodus from Egypt.
For children, the Passover Seder can be a long time to sit. During the time the plagues are recited, some families will have objects symbolizing each plague.
For example, the plague of darkness can be shown by wearing sunglasses. For frogs and locusts, small plastic toys can be thrown around the Passover table.
Judaica shops sell bags of plagues. Besides being fun for the children, the adults can have a good laugh.