Illinois Open was an mACF collegiate open tournament held at the University of Illinois in Urbana-Champaign starting in 2002 or so. A variety of people from the University of Illinois have been involved in the editing, which most notably included successful iterations by Mike Sorice. It was typically of "Regionals-plus" difficulty.
The sixth Illinois Open was held on November 12, 2007. 7 teams competed, and team Another Victim of the Manocentric Maleocracy (Jonathan Magin, Eric Mukherjee, Jerry Vinokurov, and Matt Weiner) won with a perfect 10-0 record. Seth Teitler from Chicago Random Street Corner was the leading scorer.
In addition to the main tournament itself, side events were held, including a literature subject doubles produced by Andrew Hart et al, a difficult experimental doubles tournament produced by Ryan Westbrook, and the inaugural in-person ACF Pyramid tournament.
The 2008 Illinois Open was written by Trygve Meade et al. and was won by Minnesota A, consisting of Brendan Byrne, Andrew Hart, Rob Carson, and Bernadette Spencer. Paul Drube was the top scorer. Side events included TRASH Regionals on Sunday, an Impossible Speedcheck tournament written by Andrew Hart and RMPFest.
For the 2010-11 school year, Ike Jose wrote the non-science questions for a much, much harder Illinois Open, which was above usual ACF Nationals difficulty. The set was, on the whole, poorly received. Side events included a philosophy/thought side event called "Wissenschaftslehre."
Illinois Open was not held in 2012 or 2013 and is unlikely to return.