I have the sock needle set, too. I got it from JoAnn with a 40% off coupon.
I've been meaning to put together a project for the car. Usually I know when a long wait is ahead of me (or possible) and I just throw my current project into the car/my luggage on the way. I'm divorced now, so 99.9% of my car time is spent driving, and I try not to knit then.
I've been wanting to make some washcloth/guest towel sets; that sounds like the perfect mindless car project!
Thanks for the great idea, Nikki!