From 1996 to present, the most common clue in The New York Times daily crosswords has been "See 17 Across." Here's the statistical breakdown.
For you non-initiates, the reason 1996 is important is because that's when Games Magazine's (and NPR's) Will Shortz took over the New York Times crossword from the late and unlamented Eugene Maleska, who drove the Gray Lady's happiest feature straight toward the earth's core. (And he was at the job so long that he damn near succeeded.) In my current job, which involves reprinting very old clunky crosswords, I've learned to dread seeing Maleska's byline. "How many crappy ideas can he fit into a single grid?" you may ask. Obscurity? Alternate spellings? Punny clues so unfunny they actually deaden the spirit? A theme as dry as melba toast? He can do it all in a fifteen by fifteen and not even break a sweat. Then he'll insult you for failing to notice his brilliance. Ugh.
Anyway, after seeing the statistics for Will Shortz, I was wondering what the most common crossword clue might have been under Maleska's tenure. I think it might be:
Which is about the dullest clue for ERA that I can conceive of. (Other factoid: ERA's the most common word in crosswords. Not a huge surprise, I know. But did you know that ELI is fourth, beating out such stalwarts as ALOE, EDEN, and ALE? Now you do.) I wish I could have a more entertainingly bad clue, but this is Eugene Maleska, and sometimes suckiness isn't entertaining.
On a related (and happily non-sucking) topic, the crossword documentary Wordplay, featuring Will Shortz, Merl Reagle, Bill Clinton, Jon Stewart, Bob Dole, and every single one of my friends, opens this weekend. As of this writing, it's got over 85% positive reviews from Rotten Tomatoes, which makes it one of the best reviewed movies of the year, and a damn sight better than Nacho Libre. Go see it when it arrives!