Creative free advertising?

I am looking for creative, free advertising/promotional ideas for an event that I volunteer for. We already have paid advertising (like radio ads and such), but I am looking for free (or cheap) ways that are different than the normal routes.

We already have the usual, like posters and being linked on various sites. We also created a MySpace page for the event.

Does anyone else know of other ways to promote an event? Thanks!

Many of the "local" papers in a given area carry an events calendar which would be free to you to have your event listed. Typically these come out on a Friday for the upcoming weekend. Get copies of all these papers and the contact information will be listed or go to the different paper’s websites to see if the same is listed under a contact us section under community relations or possibly promotions, etc. Community calendars exist in cyberspace too. Type in your area plus community calendar into a search engine to locate these.

A few examples near where I used to live:

http://www.bucksnet.com/mall/bucksboard/dates.html

http://doylestownalliance.org/calendar.cfm