To make punched paper snowflakes, start by printing or drawing a snowflake. The more complicated the design the longer it will take. I found some snowflake coloring pages from First Palette. Attach the coloring page to a sheet of cardstock or colored construction paper by stapling the four corners.
Lay the paper on a carpeted area and use a pushpin to punch holes along the lines. If you make the holes too far apart it will be hard to tell what the design is and if you put them too close together you'll actually cut out the shape. We checked the design every once in a while by turning the paper over and holding it up to the light. (Obviously, if your child still puts things in their mouth or you think they will hurt themselves with a pushpin this isn't a good project for them.)
Once you've punched all the lines, cut around the snowflake shape. Be sure not to cut right on the outer lines of your snowflake or you'll lose some of the design.
Separate the pages and you're ready to hang your finished snowflake in a window to catch some winter sunlight.
Books about snowflakes:
Snowflakes Fall by Patricia Maclachlan and Stephen Kellogg portrays life's natural cycle. The snowflakes fall and return again as raindrops so flowers can grow.
Snowflake Bentley by Jacqueline Briggs Martin and Mary Azarian tells the true story of Wilson Bentley, who spent his life studying snowflakes.
The Story of Snow: The Science of Winter's Wonder by Mark Cassino answers questions about the science of snow and features photographs of real snow crystals.