I'm not sure exactly where I have been for the last decade or more, but it never occurred to me to use coffee filters for snowflakes. Not even when I watched my younger kids struggling to cut through folds and folds of copy paper. Maybe I didn't think of it because I was never actually coherent in the mornings when I would see a coffee filter.
I wish I had used them earlier, though, because even when you fold them a bunch (and the more times you fold a paper snowflake, the more intricate the design will be), they are still easy for little hands to cut. They are also already symmetrical, so you don't have to square them off. And if you want to be all fancy, you can easily dye coffee filters just by dripping or spraying on a little water tinted with food coloring. Just dye and dry them before you cut them for the best results.
So if you want to decorate your house with easy to make snowflakes, grab a coffee filter and spread it flat:
Fold it in half:
Fold it in half again:
Fold it in half another time or two, until you get a shape like this:
Now you're ready to start snipping the sides. The only real rule is that you don't snip all the way from one side to the other, because that would chop your snowflake in half. And nobody wants a sad snowflake at Christmas.
You can make curves or cut straight. You can cut deep or shallow. Once you have snipped away to your satisfaction, your flake will look somewhat similar to this:
I like to cut a diagonal design in the wider top. It is fine if you leave it, but the snowflake will be round instead of having points all around it. The pointy end will be the center of the snowflake. If you want a hole in the center, you can take a small snip off the pointy tip.
And now it's time for the great reveal! Carefully unfold your snowflake: