Last month at the Norwegian demoparty Kindergarden, Gloom and Kusma of the group Excess released a short and stylish PC demo: cortex sous vide. Here is a video of it on Youtube, but if you have a decent PC I recommend you to download the actual demo and run it to enjoy the slick rendering. Kusma later announced they were releasing the source code of some of their demos.
Ealier this year, on Easter, the group Dead Roman released at The Gathering a very unusual production, spheres on a plane, that impressed me both technically and artistically. Here is an article on the thoughts and work behind the demo: Behind the spheres on the plane.