This fitted cowl neck sweater looks so comfortable, it's from Athleta, the Gap corp athletic wear website and supposed to be good for yoga, but honestly I think it looks good for a lot more than that. Certainly if you have to go about your day after yoga (or whatever you do at the gym) and don't have time to change it is perfect, mainly because it looks like a great regular sweater.
It comes in this ice blue as well as a purple. It used to come in gray but it looks like they sold out. It's made of nylon so it will hold it's stretch and can probably be machine washed and drip dried. Sounds great to me. The cowl in the photo above is stretched over the shoulders, but it can also be worn as a standard cowl.
Oh, and a bonus, the sweater also comes in plus sizes.