Though we got a hint of things to come, Microsoft capped its E3 press briefing today with the announcement of Halo 4. The brief trailer showed off Master Chief picking up where he left off, being awoken by Cortana and finding himself in the wreckage of his ship. The trailer mentioned a holiday 2012 release.
Microsoft's Don Mattrick called it the start of a new trilogy for Microsoft, so there's plenty of Halo on the way. The ship looks like Forerunner technology, which could hint at a new direction for the series.
BOOM video 9285