From http://www.write-better-english.com/competitions.aspx

This week (25 January 2007 to 2 February 2007), we're giving away $100 to the member who posts the best "Eggcorn" to the forums.

An "Eggcorn" is where someone confuses a correct phrase (like "hair's breadth") with a wrong phrase that sounds similar (like "hare's breath").