I loved, loved, loved The Muppet Show as a kid, and Pigs In Space was my very favorite sketch. So when I found these on eBay, my heart lept with gladness. When another set came up, I had to snatch 'em up, too.
It's a fold and mail postalette, and requires stickers to seal - curiously, it didn't come with any. So the little glitter stickers are my own touch.
If anyone has a source of Muppet stationery, let me know. I'm all over it.
