The Layer Cake cowl from Tiffany Perry is a project like that. It uses stripes of four different colors of yarn on a solid background, but you could also use more or fewer colors if you wanted depending on how much yarn of each you had on hand. It has a fun cross hatching stitch pattern that adds interest but isn’t too difficult to stitch.
It calls for DK weight yarn but could be made bigger with worsted, or you can adjust the size by changing the stitch count in multiples of 4.
You can check out the pattern and grab a copy on Ravelry.
[Photo: Tiffany Perry.]