According to the documentation, if DEBUG is set to False and something is provided under the ADMINS setting, Django will send an email
Although it's been a while, here's my response, so that other people can benefit in the future.
In my case, what was preventing emails to be sent to the ADMINS list, when an error occured, was an application specific setting. I was using django-piston, which provides the setting attributes PISTON_EMAIL_ERRORS and PISTON_DISPLAY_ERRORS. Setting these accordingly, enabled the application server to notify my by mail, whenever piston would crash.