apparently its coming out in November
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In addition to general housekeeping and improvements, many of you are also eager to know more about plans for an official MLG playlist and/or a Grifball playlist. Right now I can tell you that we’re in contact with each of those groups and once they’ve got maps and gametypes baked and ready for deployment we’ll be working with them to get them into matchmaking. At this rate it doesn’t seem like it will happen for November but it’s something we all hope to have implemented before the holiday break. That said, you can’t rush greatness and ultimately it’s up to the MLG and Grifball organizations to iterate and perfect their own content before we can add it to matchmaking. It’ll happen, just give it a bit more time.
http://www.bungie.net/News/content.aspx?type=topnews&cid=29120also snipers playlist coming out later this month