Checklist Website

I have created a small website that provides an Online Checklist for a specific market

I would like to make it possible for members to easily add their own checklist items by either dragging and dropping from a master list or if possible to add their own.

Does anybody have any ideas on how this could be done in a way that would be simple and effective so they can personalise the individual lists with out giving them access to all of the back end functions of the site.

Are there any other plugins out there that would work with GP.

Any suggestions or feedback would be greatly appreciated.