Perhaps I am missing something here, but, you mean you want something like this :
draggable droppable1 droppable2 droppable3
<div sortable> <div sortable> <div sortable>
If so, this should be pretty easy since script.aculo.us/prototype is inside RoR. So, it should be easy to knock up your own using the building blocks, but I doubt anyone has a pre-made drop in solution where you don't have to code -anything- ;p (now watch one of the nice Railers prove me wrong There shouldn't be any problem with nesting a sortable <div> inside a droppable <div> or vice versa. It would surprise me if there was to be honest.
Kip Massey wrote: