Doing a side project with Rails 3.1 and knowing that there must be something possibly already a gem but possibly simply jquery (or another javascript methodology but have already started with jquery) that will have something like a bunch of boxes that I can populate with an array from one model to slide to an array from another model for has_many => has_many relationships (as opposed to boring drop-down selections)
ie
People (names) Host (members) +--------+ +--------+
User 1 | | User 3 |
+--------+ +--------+