One of Microsoft's greatest exclusives is coming free to Gold users in October. Bungie's Halo 3 will be made available via the Big M's "Games With Gold" promotion starting October 16th.
Before that, Might & Magic: Clash of Heroes will be available as a free download from October 1st to the 15th. The news was posted on Major Nelson's blog earlier today. For all the details on what's coming to Microsoft's online store, check out the full list here.
While "Games With Gold" may not offer games as new and "hot" has Sony's PlayStation Plus service, what you do download, you get to keep forever, even if your Xbox Live Gold subscription expires. That little bonus shouldn't be overlooked.