Entitled the After Party update, the downloadable patch includes a brand new track called The Rock and a bunch of new single-player special events. Each event "sees you play as a distinguished character from the Festival, offering the grand sum of 120,000 chips if you can take 1st place in six unique events".
New weekly challenges will also give you the opportunity to earn more chips — which are MotorStorm: Apocalypse's equivalent to XP — so there's plenty of new things to do. Evolution's thrown out a number of balance and connectivity improvements to boot.
The After Party Update is available for free right now. For more information check out the PlayStation Blog.