I knitted a yoga mat and bag for my brother's girlfriend, for her birthday. I think she likes it. I just used acrylic (for washability & durability) double stranded, and garter stitch throughout. The two colours of purple made a nice alternating pattern. It ended up all soft and squishy. When I was knitting it everyone thought I was making a scarf. I wouldn't want to wear this around my neck.
The "In Progress" shot: