Julia lives in Minneapolis (which, as she said in her email, is really not far from Chicago). Her calendar ($12) serves a dual purpose; the reverse of each charmingly illustrated monthly cardstock page is a postcard.
You could make a new years resolution to drop a line to a friend at the end of each month...a nice way to recycle, no?
Each card is 5x7. The set is available through Julia's etsy shop, Happify.