Possible bad information in the IRSL section. 

While I can't say that two episodes of "Cheap Seats" didn't feature IRSL derby (which was indeed aired on ESPN in the 1980s), at least one episode of "Cheap Seats" actually featured Roller Games/Rollergames (RGI?). This was an episode featuring the L.A. T-Birds and another team at the Showboat casino in Las Vegas, NV. A video segment of this episode can be seen on YouTube.