Major Nelson is reporting that this week's XBox Live Deal of the Week is none other than Alien Hominid HD. The game sports a two player co-op mode through the campaign both online and off. There's also four player co-op mini-games available online and off.
Alien Hominid HD usually costs 800 MS Points ($10) but is on sale for 400 MS Points ($5). This deal is valid for Gold Members only.
Source: Majornelson.com