Pre populated New Entry Is there a way to pre-populate the 'New Entry' form in the back end? 

The context here is a calendar where you can click on a day and see a list of events and have a "New Event" button. The "New Event" button should ideally open the CMS backend and pre populate the event date (and some other fields). 

We've chosen not to build a a whole new form because the events are quite complex, containing more than one matrix and assets, and it'll only be admins creating events (they don't need all the glitz).
You can have placeholders and default values, but I guess that won't be enough for you. 

You could create a plugin that injects some javascript into the new entry page that executes an AJAX call and fills these fields in.