Jenn from Endlessly Inpsired shows how she used Kool-Aid to create a dip dye effect on a pillow cover. It creates a lovely, painted effect on the pillow. She did this on a pillow cover she made herself, but you could also dip-dye a purchased pillow cover. Just be aware that synthetic fabrics may not take the dye. Stick with cotton if possible. Go to Endlessly Inspired for the tute.
[photo from Endlessly Inspired]