I encourage everyone to tune in, especially people who aren't fortunate enough to see such a Mass very often, and I would encourage positive feedback to EWTN, so they'll broadcast more! You can see photos of the amazing church from Chicago through their website.
The EWTN Mass at St. John Cantius this Saturday (Feast of Our Lady of the Holy Rosary), broadcast live at 11AM CST/Noon EST, is the Missa Normativa, the 'Novus Ordo Mass', the 'Mass of Vatican II'. I assume that, just like our normal 11AM Sunday Mass, this one will be offered in Latin. (When Mass is said in English at SJC, the unchangeable parts of the Mass are still said or chanted in Latin, in compliance with the documents of Vatican II. ("Particular law remaining in force, the use of the Latin language is to be preserved in the Latin rites" - Sacrosanctum Concilium 36).