QUOTE(CsL @ Jun 21 2007, 04:52 AM)

A shame that you have to become a XNA-Member to watch this demos

I'm not LiVE and I don't have the Money for this Membership.
"..but once things get complex, XNA gets cumbersome" (ppexcess360(dot)blogspot(dot)com) ^^
If the organizers are smart, the requirement will be that the source be provided with both Xbox360 **AND** Windows projects.
Windows XNA apps are freely downloadable and runnable. As long as your shader profile is up to snuff, you should have no problem running the demos the same as they run on the 360.