In the Simple PHP Library (SPL for those close to you), there are classes and interfaces that allow you to simply browse folders and files. It is even possible and very simple to create a filter that allows you to narrow the result.

Importing or exporting data in CSV format is a classic for a business application or a back office. Little known, the Standard PHP Library makes it easy to manipulate CSV files whether read or write via the SplFileObject class.

Background: One site offers its members to vote to elect the member of the month. Each month the counters are reset to zero. On a dedicated page, the site displays the history of the top 5 members of each month over a period of one year.