According to the latest issue of Xbox World 360, Microsoft has a few secrets up their sleeve. The issue touches on some rumoured games that are in development that "Microsoft doesn't want you to know about"... DUN DUN DUN.

While the feature mentions numerous games that most people assume are under-development - your Halo 3, Forza Motorsport 2, and Ninja Gaiden 2 - it also mentioned a good dozen other games that haven't even been announced or heard of, let alone announced for being in development. It's a little iffy and some of the titles are very unlikely, but regardless a major magazine has posted this list of games as hitting the 360 before 2007 ends.

• WWE WrestleMania 360 (if this did happen it would likely be changed to WrestleMania 23 or 24)
• The Sims 3
• Tom Clancy's Splinter Cell 5
• Star Wars: Knights of the Old Republic 3
• Jade Empire 2
• Un-titled Bioware game
• Brute Force 2
• The Chronicles of Riddick sequel
• Unreal 2007
• Turok follow-up
• Avalon
• BC
• Fable 2
• Half-Life 3
• Hitman 3
• Man With No Name
• Outrun follow-up
• PES 6
• Rallisport Challenge 3
• Next-Generation Grand Theft Auto
  

Some of those names are surprising and seem very unlikely, specifically Half-Life 3, but time will tell I suppose. You should in no way take this as an even remotely confirmed list!