I have worked on multiple keynote demonstrations. These projects involve prototype hardware and software and are usually on very tight schedules.
Mythos Labs contracted with Adobe on their “MAX Racer” keynote presentation. I wrote a Unity COLLADA exporter for Adobe’s new Flash Stage 3D. We were also contracted to create the demonstration level including modeling and texturing.
I worked with Microsoft on the Windows Phone 7 Build keynote featuring Gravity Bear’s “Battle Punks”. This project involved significant porting of C++ to XNA C# in a very compressed timeframe.