XNA Game Studio Express (http://msdn.microsoft.com/xna) is being demo'd tomorrow at X06.  It's pretty awesome too.  I got a chance to see the demos and i think the attendees will be pretty impressed.  Essentially XNA GSE allows anyone to build games for Windows or XBox 360 without having to buy any special hardware and the tools are all free.  If you're not attending X06, then swing by the Game Camp we have planned where we'll take this new tool through its paces and show you what you need to get started.  Here's the link to register for Game Camp: http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032312244&Culture=en-CA