On the 16th of July the Canadian post issued a pre-paid envelope bearing a printed stamp picturing a cute frog. The enevlope is sold with a card bearing the same picture.
Here is the envelope and a zoom on the "stamp".
Here is the card.
This envelope is part of a series called "write me back". The idea is that you send a note to your friends, putting the card and the enevelope in your letter so thatthey can write you bakc. Several designs exist in this series.