Some time ago, I entered a blog about panblurring. In short, panning a flying or running subject with a relatively slow shutterspeed will render the subject sharp and the background as pleasantly colored streaks.
With non-moving subjects, you can extend the technique to what is known as zoomblurring. Just frame your subject as you always would, but make sure you have a relatively slow shutterspeed to work with. This can be anything between 1/30th of a second and several seconds. Just try and see what looks best.
During the exposure, zoom your lens in our out. If you do not have a zoomlens, you can always try to use your footzoom and run towards your subject (or away from it) during the exposure (not!). This technique can lead to some very interesting results, either very beautiful or utterly ugly. Just don’t use it too often or it will quickly become a gimmick, but keep it in mind as just another crayon in the photographers box.
Last year in Norway, we had a very drab day, but at the end of the day the sun finally peeked through. There were some very nice pastel colors in the sky, but I could find no decent foreground in the few minutes that the sunset would last. So I zoomed in tightly on a mountain ridge and used the zoomblur technique. I like the result, but of course your mileage may vary.
Norwegian sunset; Canon 20D w. 70-200/4; 1/15s at F11 and ISO 200; Beanbag from car roof.