In the supermarket Lou refers to Homer and Marge as the Los Angeles Clippers of doubles tennis. At the time (early 2000s), the Clippers were regarded as the worst NBA franchise in history.
Homer mistook tennis for foxy boxing, but didn't know what it was called. He referred to it as "the sport where the chicks whale on each other." Previously, however, in "Lisa on Ice", Homer knew the name of the sport (when he was telling Lisa that girls should stick to "girl sports," like hot-oil wrestling and foxy boxing) and earlier in, "Homer's Night Out," Homer took Bart to a strip club that was hosting a foxy boxing match in his search to find Princess Kashmir and apologize to her.
However, given Homer's mental capacity (and the terrible continuity of the show), he (and the writers) could have easily forgotten.