A fun way to learn word families… twist the egg to sound it out and read lots of first words!  Along with the number activity, they could also be an Easter basket prize.  We just started playing with these and they are fun!  You can even put a treat inside for when they finish the words on each egg.
Word families include:
at – bat, cat, hat, mat, pat, rat, sat
en – hen, men, pen, ten
ob – bob, cob, job, lob, rob, sob
ar – bar, car, jar, far, tar
ot – dot, got, lot, not
ad – bad, dad, had, lad, mad, sad
ug – bug, dug, hug, rug, tug
ook – book, cook, look, took
Source:  Living and Learning