Month View Info Display

My client has asked to change some of the data being displayed in the Month View. Currently it shows the event name. They'd like to change it to the associated Contact - which is related data.
I've seen the calc field on the layout (CalendarContentReptCalc) which is is a bit cryptic due to the variables. Before I spend a couple hours tracing the calculation backwards - can anyone tell me where I can quickly modify the calc for display. I've seen the z_AlternateSummaryCalc field in the Events table and can modify that easily - but where does it get used down the chain to populate the CalendarContentReptCalc field?
I've seen the calc field on the layout (CalendarContentReptCalc) which is is a bit cryptic due to the variables. Before I spend a couple hours tracing the calculation backwards - can anyone tell me where I can quickly modify the calc for display. I've seen the z_AlternateSummaryCalc field in the Events table and can modify that easily - but where does it get used down the chain to populate the CalendarContentReptCalc field?