No, that's not a typo -- there really is new downloadable content for Guitar Hero II. The "Indie Label Pack II", which retails for 500 MS Points, includes such non-chart-toppers as "You Should Be Ashamed of Myself" by The Bled, "Memories of the Grove" by Maylene and The Sons of Disaster and "The State of Massachusetts" by Dropkick Murphys.
You may be wondering why new tracks are coming out for Guitar Hero II, and not it's younger, fresher brother. Well, it's easy to forget that while Guitar Hero II and Guitar Hero III are technically part of the same series, they belong to two very different developers. We imagine Harmonix is trying to sweeten the deal for those who haven't decided which iteration of the game to pick up for the holiday shopping season.
We're just glad these tracks didn't come to Rock Band -- if your roommate's drunken, warbling impression of Dropkick Murphys frontman Alex Barr doesn't get you kicked out of your apartment, we don't know what will.