A very common web UI task that we are tasked with are dual combo boxes. These are very good if you want to manipulate or assign several items at once.

Below is a working sample of a Knockout JS way of doing one of these. I really like the result of using an MVVM framework to do these because the whole select -> option DOM manipuation is completely removed from us, Knockout takes care of that part. As a result, we are no longer using tons of jQuery magic; instead, we are dealing with the actual objects that will ultimately be sent over the wire.