I love rubberbanding and twisting. Take your shirt or scarf or whatever and take 2 inch sections or so and twist them then rubberband them off and keep doing it until the whole shirt/scarf is twisted and rubberbanded every couple of inches. It makes really cool rings of color with a bit of white between.
Be careful what colors you put next to each other - put colors that blend well. If they touch they create new colors so be mindful of the colors you will get - blue and red next to each other will result in some purple. If you put something like orange and purple next to each other and it runs a bit you'll get a yucky looking muddy color.