We have family that lives in Jericho Center, Vermont, so we're familiar with the work of Wilson Bentley, also known as Snowflake Bentley. Bentley "captured" and photographed more than 5,000 snowflakes, each on unique. Like birding or catching frogs, checking out snowflakes is a great way to connect kids with nature, especially when school is cancelled.
The Bentley Website says:
From the earliest memories of our childhood, many of us can remember hearing the phrase "no two snowflakes are alike". This discovery was made in the small rural town of Jericho, Vermont by Wilson A. Bentley (1865-1931).
Check out the Snowflake Bentley Site here. Lots of good info and links.