With this new mediawiki extension you can add <tasks>something to do</tasks> into any page. The new according special page, Special:Tasks will then search all tasks from all pages and sort them by priority.
Usage
<tasks> [ ] Regular task (Owner User). [1] High priority task. [2] Medium priority task. [3] Low priority task (Owner User). [!] Urgent task. [x] Closed task. </tasks>
Example
<tasks> [2] Show the Task Extension to users [x] Go to work </tasks>
Now check Special:Tasks.