Dynamic Field is a CCK field that returns a textarea where you can enter custom PHP code. The code is computed real-time and lets you access Drupal objects like $node, $user...
Language Checker module provides a tiny little overview page which lists each installed module's translation percentage for each enabled language, and overalls.
Taxonomy Cloud lets you pick Drupal Taxonomy Terms is an intuitive flash interface. This module returns a block for which the dimensions and the colors can be customized.