I just updated the PDC demo project at http://electricbeach.org/files/SnowboardSketch_Demo_PDC.zip

The original post contained some references to the Expression Blend sample behaviors (which you can download at expressionblend.codeplex.com), but it seemed easier to make the project stand-alone by removing the references, as the samples were only used to show of the MouseGestureTrigger.

If you do want to play with that (which is great fun), just download the sample project on its own.

Regards,
    CS