According to
Fusible (Thanks Joystiq), several domains pertaining to Halo Spartan Assault have been registered by MarkMonitor, a service affiliated with Microsoft.
Variations include SpartanAssault.net, HaloSpartanAssault.com, Halo-SpartanAssault.com, Halo-SpartanAssault.net and HaloSpartanAssault.net, sugessting the title of a future product in the Xbox flagship franchise.
There has been no confirmation from Microsoft as to what they might be attributed to yet, but name of the recently announced live action Halo TV series, to be produced by Stephen Spielberg, is one possibility.