What's your favorite use of Drush vset?

The more I learn to do with Drush, the more efficient I become. One trick that's saved me a lot of time is setting certain Drupal variables with the vset command instead of clicking through the standard admin interface—for example, putting the site in maintenance mode by setting site_offline to 1. Here are four variables I find useful to set via Drush. What are everyone else's favorites?

Edit: Attached is a pretty little printable cheatsheet of my favorites, for anyone who would like it.