This phenomenon can perhaps be more accurately explained through the use of real world examples, of which here are two:
The 206 bus from Kilburn to Willesden
The 206 is a perfect example of a temporal recipriversexcluson; that is, any time actually given on the bus stops, signposts, or, in fact, any media in the known world as the supposed time of the bus arriving is in reality the only time at which it is physically impossible for the bus to come.
This theory was further strengthened when the usual authorities changed the stop times to reflect the nature of the 206's changing arrival time, whereupon the 206 immediately stopped arriving at these new, revised times, and now occupies a dangerous portion of temporal recipriversexcluson-space where not only is it impossible for it to arrive when it is expected to, it is now virtually impossible for it to arrive at all.
Your mother-in-law's birthday
A high-level reverse temporal recipriversexcluson, your mother-in-law's birthday will fall on the one day of the year that you are definitely certain it could not possibly fall on. In fact, you are so completely sure that her birthday is not on this day, that this is the only possible reason why you would pick this day, out of all the days in the year, to go watch the rugby/football/strippers with your friends.
Other interesting observable phenomena concerning this event are that this date can (and will) change from year to year, independent of whether or not you write it down, put in your Palm Pilot, or carve it into the skin of your upper thigh. | 
