Nice Menus enables drop-down/right/left expandable menus. It uses only CSS for most browsers, with minimal Javascript for IE.
Drupal module that adds a voting widget to nodes
Drupal module that provides a faster functionally equivalent alternative to the views "Search: Index" filter.
Drupal video tutorials for fast learning
Screencast that provides a 12 minutes overview of the Digg this and Service links modules.
This module adds a Digg this button to your nodes.
Module to add Web 2.0 (video) abilities to drupal
Nice tutorial for drupal Web 2.0 (video) abilities