The Google SketchUp 3D Challenge is a weekly modeling challenge hosted by The Google SketchUp 3D Challenge Blog (http://sketchup.google.com/3dwarehouse/cldetails?mid=572b254a232ee37b70eed953ff2880fe). Any and all SketchUp users are welcome to participate. Models are created, uploaded to the 3D Warehouse, then voted on by fellow users and modelers. Past challenges include Deep Sea Residences, Staplers, Airplanes, Chess Sets, and many more. Complete guidelines, directions, results, and examples can be found at the blog's website. http://sketchup3dchallenge.blogspot.com/