Enhancement: Autovalidate. Check out how it works for pages. Basically, if users has admin rights for the plugin then autovalidate their submission. If not then pass to validation queue.
Bug: When adding an event and I force it to fail validation, the expire time gets silently incremented by 2 hours when page is returned.
events.add.inc.php line 127:
Enhancement: Redirect to events.php after adding an event. [Just like after deleting an event; therefore consistent].
Bug: Whilst trying out plug.php?e=calendar&c=CAT_CODE I got a 'wrong url' error. Turns out that the category I made wasn't in the cache so I had to purge the cache for it to work. Don't really know if that's avoidable, just thought I'd bring it to your attention.