Actually, it's a similar principle to that of the time travel causation paradox. In it, a time traveller goes back in time to cause or prevent something. If this succeeds, there is no longer any reason for the traveller to go back in time; it has already been accomplished. Thus, the traveller doesn't go back in time, causing the event to switch back to its original state, causing the traveller to go back, causing the event to switch again, ad infinitum.
Similarly, the least interesting person in the world would suddenly become the most interesting, causing (him|her) to no longer be the least interesting, and the second-to-least interesting person becomes the least interesting person.
Now, however, the person is no longer the least interesting so, the lack of interest being the interesting part, (he|she) becomes the least interesting again.
According to my current thinking, the solution to both paradoxes is the same: the world will oscillate between the two states infinitely fast, thus causing, in effect, the two states to become superimposed, distinct states. Hrm. Now that I mention it, quantum mechanics, anyone? :)

Erm, the sign ahead says, "Zebra crossing." Should I be concerned?