If you ever used Drupal 6 you must know with the Bluemarine theme which is one of a few theme that included with Drupal 6. And for users of Drupal 7, you can also use it because the theme now live as a contributed theme.
I personally have very special memories with this theme, why? I first learned to make Drupal theme based on the Bluemarine theme.
Bluemarine currently managed by John Albin, and is now being sought who will maintain it to make Bluemarine still evolving, this theme has its own history of Drupal, so the existence is worth to thinking about.
Interested to become its maintainer? you can visit this page.