Xbox Live Marketplace was just recently made available on the Xbox Live website. Instead of having to browse, purchase, and queue the content on the Xbox 360 directly, you can find content and queue downloads to your 360 with a few clicks (and spend your points even quicker!) A probable unforeseen bonus for many (which will be fixed soon more than likely) is most people can now receive some limited content!
There are many scenarios where a user could receive a special code for limited content; preorders and limited edition games often come with some extras. When you use these codes on the browser based version of Xbox Live Marketplace, it has been found that it takes you to a publicly available URL to purchase and queue the content! What does this mean for you? At this point, it seems a lot of content that has been recently removed from the marketplace (Left 4 Dead demo, recently removed for those who missed it) are still available, as well as other limited content such as Call of Duty 4 Picture pack, Gold Plated Lancer Assault Rifle for Gears of War 2, Bungie Day "07 content, and more being found as the day progresses. Several downloads were found that cost 99999 points as well (what a deal!) There is a group of people on SlickDeals who are gathering a list of this extra content as it is found.