I'd like to see year-over-year data for cons you have information on (attendance figures, price, dates, guests) represented in some sort of graphical form. The most obvious use is for modeling con growth over time, comparing growth rates, dips, etc. and modeling the data on multiple cons based on geographic location and time. I think this functionality would provide an interesting look into the evolution of cons in different areas of the country / around the world and possibly show how dates and competition effect growth rates.