I was experimenting with Tunisian crochet stitches and came up with this one that looks like knitted garter stitch. It uses two colors, the first color to pick up stitches and the second color on the return pass, which is done by turning your work and working in the same direction as the first pass, so both yarns end up at the end of the row. This requires a double-ended tunisian crochet hook.

The ridges make a great wash cloth, and I love how the colors mesh when you use a yarn with lots of different colors. Also, the pattern is the same on both sides.
I have included some photos to help explain how to work this pattern, but it is fairly easy if you know how to do Tunisian crochet.