From 1992 through 2006, 58 position players pitched in major league games. This year, 54 have already done so. In that 15-year period, a fan who watched every game his or her favorite team played would have seen a position player pitch once every four years, making it a true novelty. The same fan would have seen it three or four times already this year.
Even at this frequency, a position player pitching has some entertainment value. Relative to the low-leverage alternative -- the forgettable last man in the bullpen, who throws just like any other pitcher but a few percent worse -- a position player offers a different set of emotions and a bit of unpredictability.