There is a little mail slot built into the house so we would stick random paper and junk mail through it for fun. I thought it would be cute to have something Gabby wouldn't crumple so easily and that she could reuse. Since Valentine's Day is next week, I figure it'll double as a Valentine for her as well.
DIY Felt Valentine's Day Envelopes:
You've Got Mail:
Small Envelopes for Small Hands: