Create some themed Valentine's Day games with hearts cut out of construction paper and a large stack of red and pink balloons!
Heart target game:
Cut some large hearts out of red or pink construction paper and scatter them around the room. Blow up balloons without knotting, and give them to your children to "set off" into the air - seeing if they can land any on a heart target. If you have more than one child playing, the winner is the child whose balloon lands closest to a target! For older kids you could number the targets and get them to keep score.
Cut a heart-shaped frame out of corrugated cardboard, paint it red or pink, and either suspend it from a doorway or prop it up diagonally between a chair and a wall - you might need to improvise! The children then try to bat their balloons through the heart to score a point.
Valentine balloon pop:
Pour a small amount of Valentine confetti into your balloons before inflating them and tying off. Give the children a pin and ask them to keep the balloons in the air until your signal, at which point they can start trying to pop them! You could also put a small piece of paper with a heart drawn on it into one or two balloons - and whoever retrieves those wins a prize.