Asana! They have a board view and you can just create a project that is a 'sprint' by adding categories and putting it in the board view. And then add tickets from other projects to the sprint and drag them through different states. And it's free.
Mobile app is also very very good which means you can easily update or use it to make tickets while on the go...or in bed.
Mobile app is also very very good which means you can easily update or use it to make tickets while on the go...or in bed.