Fixing the 'blank' screen problem
I notice a few people are having problems with running the sample code. I experienced the same problem with SimpleRacer running on the 360. It's pretty simple to fix though!
There are two files which appear to be 'missing' when the game runs. These are "AlphaDeadTree.X" and "TrackSimple.Track". Both are in the content folder but are not added to the 360 project and as a result are not deployed to the xbox - hence file not found.
Right-click on the content folder and select 'Add Existing Item' and then choose "AlphaDeadTree.X" from the content folder on disc.
To add "TrackSimple.Track" is a slightly different process. Choose 'Add Existing Item' as before but in the file selection dialog, change the 'File Type' dropdown to 'All Files' then locate and add "TrackSimple.Track". Once added, you need to right-click on "TrackSimple.Track" to access it's properties. Then change its "Build Action" to "Content" and select "Copy If Newer" from the "Copy To Output Directory" option.
I suspect any other blank screen problems are caused by this and I recommend people run these examples in DEBUG mode FIRST! That way, you get to see the error messages which occur at two points where files are loaded. By hovering over the filenames these sections are trying to load, you can see what you are missing and probably locate it in the content folder.
Hope this helps!