Igloos are cool. What kid hasn't wanted to build an igloo? You can easily build an milk jug igloo in your classroom with some planning, lots of milk jugs and hot glue. This could be a fun winter craft for the kids when it's too cold to go out.
Travel to a galaxy far, far away when you make a Paper Plate UFO Craft. Paper plate crafts for kids can be really cool like this one, which completely transforms the everyday objects. Make a flying saucer like this and you'll be worlds away.