Hopefully you don't get behind someone who is hearing impaired or has limited hearing.
Here's an interesting article:
http://www.bicycling.com/article/0,6610,s1-1-283-13276-1,00.html
This is great!
Last months issue of Bicycling magazine had a little blurb on event planning. It's online here: http://www.bicycling.com/article/0,6610,s1-1-323-19191-1,00.html