Here there is a beautiful mask for a Frozen Party, for Carnival or as a party souvenir... You can even just give it to your children to play!
If you want to print them in a poster size, you can use "posteriza" (free download).
Remember to do a right click before saving, for having the image in its best quality.
Check out this nice Amazon Recomendations for your Frozen Party!
Check out the whole Frozen Free Printable Kit!