- This page was last updated on 5/29/02 Problems with this site E-mail Britt Be Sure to check back again - as we are updating the web site on a daily/weekly basis! Decatur Celebration has made its mark on the Midwest as Illinois largest FREE family street festival and has been dubbed by its loyal attendees as The Worlds Fair of the Prairie . Now in its 17th year, the event is expected to attract ...decaturcelebration.com