For the MATHCOUNTS Problem of the Week blog, there is an archive located on the right side of the page that lists all of the posts by month and year. Click on one of these links to access the archive, and navigate to find the desired post.
Additionally, there is a link that contains all of the problems called the Problem of the Week Archive. This archive contains links to the problem posts themselves, as well as PDF downloads for each individual problem and the exact date and title of each post. It's possible to refine this list with a drop-down menu located on the top of the list, to locate specific problems in subjects such as logic or geometry.
Other Problem of the Week archives impose a similar system for archival and may be navigated by locating the specific month and year of the problems. This system is found in Macalester College, Purdue University and other educational organizations, used as a method to stimulate interest in mathematics. Some problem of the week programs invite anyone in the school to submit solutions, such as Purdue University, and provide prizes and certificates for sending in a certain number of correct solutions over a semester.