Module to create nodes that are lists of other nodes? I'm looking for a way to allow users on my site create a piece of content that is a list of current content. For example a user can create a "favorite articles list" content piece and then select his favorite existing articles that will populate this new content type. 
Is there an exisiing module that does this or something similar?
You could probably try the Flag module. It doesn't create nodes, but the idea is pretty much what you're lining out.


  Flag is a flexible flagging system that is completely customizable by the administrator. Using this module, the site administrator can provide any number of flags for nodes, comments, users, and any other type of entity. Some possibilities include bookmarks, marking important, friends, or flag as offensive. With extensive views integration, you can create custom lists of popular content or keep tabs on important content.
  
  Flags may be per-user, meaning that each user can mark an item individually, or global, meaning that the item is either marked or it is not marked, and any user who changes that changes it for everyone.