Party-In-A-Box: Mailable Birthday Celebration Kits

I have a stockpile of materials to make festive kits to send my friends on their birthdays: garland, banners, paper crowns, confetti, and more. I have them all in a box that includes packing envelopes so they're easy to assemble and ship. It's a way to celebrate with them even though I can't be there to celebrate with them!