***Update***
Halo 4 has been confirmed for a November 6, 2012 release date. Read more here!
***Original Story***
Microsoft and 343 Industries is teaming up with Team Coco (Conan O'Brien) with Halo 4.
We don't know how, but according to Microsoft's Major Nelson, Conan O'Brien "plays a part" in Halo 4's release announcement.
"Look for #Halo4 news on the way in the next 24 hours. Hint: @TeamCoco plays a part!" Microsoft's Major Nelson said on Twitter.
Halo 4 senior producer Alison Stroll had a similar tweet, "A little birdy (or was it Andy?) told us @TeamCoco will have some big Halo 4 news tomorrow. Stay tuned! #incoming #wakeupjon."
According to The Verge, "reliable sources close to Microsoft" claim Halo 4 will release on Tuesday, November 6th, 2012. They also say Microsoft will make an announcement about the game's release "before noon ET" today.
For what it's worth, Team Coco didn't mention anything Halo 4, but did retweet Nelson's post. Be sure to check back today for more Halo 4 release date news.