Creating a contextual filter for a view based on month and day I've created a content type that represents a past events. I've added an extra date-field to this content type that indicates the date of the event.
I'm trying to create a calendar that groups events by day and month, but ignores the year in which the event happens.

e.g. when going to site.com/calendar/[month]/[day], I'd like to get a list of all events that happened on the given day of the given day, irrespective of the year in which they happened.

This seems impossible with the default tools, as they always expect a year to filter on. How can I customize these filters?
You will find the Date module useful for this. Date contains a number of sub-modules, including Date Views. Enable the Date Views module (and its required modules) and you will have what you need in Views. 

Here's a link to the module:

http://drupal.org/project/date