There's nothing more heartwarming than watching your children perform Christmas songs to the rest of your family at Christmas! If they are old enough to talk and in a playgroup then it's likely that they've already learned at least one or two festive songs that youcan encourage them to perform to grandparents over Christmas. If they aren't yet singing, then put on some festive music and encourage them to wiggle in time with the music!
Ask older children to act out the nativity story, playing the different parts. Acting forms a fundamental part of pretend play that is so important in developmental terms.
You will be proud, the grandparents will be moved and your little ones will be delighted! Practice a few songs or stories now so that they're ready for the big day, and have them bring the house down for their Christmas debut!