“Bring Down the Sky” is the first in a series of planned downloadable content that will further expand the Mass Effect story and universe. The package will be available at the launch of Mass Effect for the PC, and will be free of charge. It includes a new uncharted world that introduces the deadly Batarian alien race, approximately 90 minutes of new gameplay and an original soundtrack. Batarian extremists have hijacked a mobile asteroid station in the Asgard system, setting it on a collision course with the nearby colony world of Terra Nova. Only Commander Shepard can save the millions of innocent civilians before the asteroid completes its deadly descent.
Screenshot: New Batarian race

Then again, call me old fashioned but I personally believe that 99% of DLC out there today should be free.
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