One of the best free games on Xbox Live Arcade, Doritos Crash Course, is getting premium downloadable content in the form of City Lights, will will cost 160 Microsoft Points ($2 USD).
The DLC10 new levels to London and Las Vegas, and adds new versions of the regular Japan courses as well. New Achievements are added as well.
For those of you nervous about spending money for DLC for a free game, there's a trial version of the DLC as well.
Doritos Crash Course was first released way back on the 10th December 2010, and earned very positive reviews.