Major Nelson has announced that the two games gracing Xbox Live Arcade this week will be Lucidity and South Park LET'S GO TOWER DEFENSE PLAY. The first is a puzzle platformer from LucasArts with a positively delightful art style, while the second ... well it's pretty self explanatory. It's a tower defense game set against the backdrop of the famous, quiet little mountain town. Both can be yours in exchange for 800 ($10).