A long time ago I did a funny discovery. It totally slipped my mind until MoGraph was announced.
Here is the result, read on to discover how it is done.
Well actually it is quite simple.
Place a plane just in front of the camera.
Add a transparent texture with some refraction (1.5) and with a bump-map. The bump-map will make the effect, so play around with noise or textures or even images.
You can also add an image to the transparency channel to get weird effects like this.
and so on