filter by group w/JQuery

create filter by group - give two options: 1) textbox with JQuery autocomplete from database, or 2) tag cloud sized relative to size of group membership (or maybe sorted by click popularity on this particular site?). Wrap this in a div that can easily be expanded/contracted to use space efficiently and attractively, maybe in a format where a few are displayed at first, then a "more" link is provided to show more options.