You might know that according to the NTSC standard for TV signals in the USA, the display is updated 60 times per second. But did you know that it's not exactly 60 - it's actually closer to 59.94 (60000/1001, to be exact). This Wikipedia article explains why.
Early microcomputers (including early PCs), which were designed to be plugged into TVs, didn't have exactly the same frame rate as TV pictures - most of them used 1640625/27379 (which is closer to 59.92) instead because it was slightly easier to build that way (fortunately TVs have enough tolerance to display the slightly out-of-spec pictures correctly). I wrote this to explain (amongst other things) the origins of these "magic" numbers.
This 59.92Hz number turned out to be very important for finding an obscure bug in California Games that I was hitting whilst trying to get the "CGA MORE-color mode" working on MESS. There is a routine to determine if the frame rate is close enough to 60Hz for it to be likely that this effect would work. The routine seems to be trying to determine if the frame time is in the range (1/60)s +/- 500us (presumably the authors didn't know that it was actually supposed to be closer to 59.92 than 60). However, it puts the timer chip in the wrong mode, causing it to count down twice as fast. So in fact it is instead determining if the frame time is either in the range (1/60)s-500us to (1/60)s or in a similar 500us range at around 1/120s. The "normal" value lies right on the edge of the range it's actually measuring. Of course, because on real hardware the rate is 22us less than (1/60)s (pretty reliably so, since they are based on the same clock signal) this works fine in practice, but I'm sure it's not what the authors meant!
This bug was preventing the mode from working on MESS because the MESS frame rate was set to exactly 1/60s (slightly too fast) and frame rate test was failing (but only just). The fix is for MESS to use 59.92Hz frame rate instead - by making the emulator almost imperceptibly more accurate, the effect works!