A couple weeks ago, I posted about self-striping yarns. Another fun way to play with colors is using "multis", where each strand contains multiple colors. Whereas self-striping yarns change gradually, multis have either short bursts of color change or different colors plied together. You can see how the Nature's Choice Organic Cotton in Wildflowers (left) has short color changes that won't create stripes when worked up. Hometown USA multis (shown in Mardi Gras, right) have contrasting colors spun together; it's as if you were holding a strand of each color and working them at once.
Here's a project in each of these yarns so you can see how these fun colorways work up (click on the image for the pattern):
What's your favorite project to spruce up with a multi-colored yarn?