Or InCoWriMo as the cool kids call it. If Month of Letters isn't enough for you, why not take on this project as well. It's a similar concept. Write one letter, everyday of the month. You can take a picture of your letter and submit to the InCoWriMo site. It might be their "Letter du Jour" on their blog. They even have a list of 28 people who would love to get a letter from you.
P.S. The stamp in this post is the 2014 Global Flat Rate issue. It hasn't been released yet, but I can't wait!