Together with Shavuot ("Pentecost") and Sukkot ("Tabernacles"), Passover is one of the three pilgrimage festivals (Shalosh Regalim) during which the entire Jewish populace historically made a pilgrimage to the Temple in Jerusalem.
While the nursery is part of a progressive Jewish synagogue (rather than orthodox), they observe the Jewish holidays and involve the children in the preparations and celebrations, as a secular nursery/school would do for Easter or Christmas. For nursery this usually includes inviting the parents to join with the singing and blessings.
For the 'Tots Pesach', the children have been asked to come dressed in a costume relating to Passover - suggestions included 'Israelite slave, Pharaoh or Egyptian costume, or one of the plagues, eg frog, wild animal...' Some of the plagues are quite frightening ('blood', 'boils' and 'darkness' are not even the worst). We have elected to play it safe with frog, so Milo will be going to Nursery tomorrow dressed like this -
