Just an idea - and I might be doing this, if I don't have a flash of inspiration soon!
If you can't get hold of postcards or (as in my case) come up with a good snack recipe you could always print your own postcard with a picture from another country and find a snack recipe to go with it.
The problem I have is finding something with simple ingredients, there are plenty of snacks both sweet and savoury but most of them have some obscure ingredient!
If you want to sign up, get your email to me BEFORE 7am Japan time on Monday. Come on, you know you want to...