Paper mache a balloon, pop the balloon, add string and a basket for spring class crafts. Could go great as a bulletin board theme (Kid's Soaring to New Heights in Reading...)
Kinder Winter Landscapes by Paintbrush Rocket, via Flickr
a geometry lesson
10 Winter Themed Elementary Art Lessons that don't involve the holidays
Floor pillows! Oh my! This is a must!
How To: Make Heart-Sewn Valentine | 10 Creative Valentine’s Crafts for Kids | Real Simple
Button art by WCS -- this would be really cute on the side of a purse, or a shirt, or....