How to install drush on a restricted shell access account? Media Temple shared environment
Place drush into your home (~) folder under something like ~/drush/
Create or edit ~/.bash_profile and add the following: alias drush='~/drush/drush'; this creates an alias called 'drush' that will execute drush's main file.
If you need to specify which version of PHP to use, add export DRUSH_PHP=/path/to/php.
Run source ~/.bash_profile to reload the .bash_profile file.


At this point you should be able to use the drush command.

In unrelated news: if you can, move your client off MediaTemple. Their database servers are in a physically different location from their web servers, which is an absolute nightmare for applications with a ton of database queries (read: Drupal).