Fasterer caching on multi-webheaded Drupal installs. This module will try to get cache items from a fast cache (probably local, like APC), then fallback to a central, consistent cache.
Module for creating translatable render arrays which are translated at the time of rendering. This makes it easier to write unit tests using simpletest because the use of the t() function makes it necessary to use the web tests due to call to the database layer. The translatable render arrays is a workaround to delay the call to the database layer and instead juggle a data structure.
In Drupal 7 we have the CSS and JS injector modules that show that often we need to inject web stuff into our Drupal sites outside the bounds of a theme or module.