I've just read Simon's diary and see that he has made his "hilarious" acryllic joke about the Cyrillic alphabet. He seems disproportionately amused by the joke. The first time he told it, it was passable in an instantly forgettable way. But some jokes are like radiation and have a half-life, getting less funny each time you hear them. I'd venture that Simon's jokes have a quarter-life - that's if they were every funny in the first place.
His Cyrillic alphabet joke has long ceased to amuse.