What a nifty idea! if you want creative envelopes, go to Maps, map the route from your letter to the other person's mailbox. Print them up, fold them into 8 by 11 envelopes (or smaller if you are sending cards). This would be cool for pen pals
Wedding Invitation Ideas: Red, White, and Blue Letterpress Airmail-Inspired Wedding Invitations by Lucky Luxe via Oh So Beautiful Paper
Turns out, I pretty much fail at making internet friends about as much as I fail at making real life friends.