Maintaining a module, theme, or distribution on drupal.org
One of the biggest, high profile, and sometimes challenging ways to contribute back to the Drupal community.
Applying for commit access on Drupal.org
Note No, it doesn't come with commit access to Drupal core– only Dries and one or two other co-maintainers per release have that.
Creating a new project (page) on drupal.org
Just like on our Drupal site at home, most things – even the most momentous things – can start with a visit to the Create content (node/add) page.
There, one of our options is Project (http://drupal.org/node/add/project-project).
What we have to know
Most of all, we have to be prepared to complete and maintain this project.