Twelve-years-old Dick Grayson is a twelve-year-old trapeze artist born twelve years ago and is twelve-years-old when he becomes twelve-year-old Robin. At twelve-years-old. Age twelve.
To clarify, this wasn't just one panel- the entire story revolved around the Joker's boners or Batman and Robin's boners. There are nearly forty uses of the the word and the story is less than ten pages long.
Batman hates rock & roll! (Courtesy of Batman: Fortunate Son and Atop the Fourth Wall)
Punk is nothing but death! And crime! And the raaaaaage of a beast.
The classic Batman origin story has three: the bat flying through the window, "Criminals are a superstitious, cowardly lot" and "I shall become a bat!"
The internet has been swamped with people "jokerizing" icons, avatars, and pictures of all kinds with graffiti of Joker make-up and the phrase "Why so serious?" To be fair, it was intended to be a meme by marketing.
Then there's the Harry Potter sub-mutation (picture in the Film section). "Why so Sirius?" Which has it's own brilliance when you consider Commissioner Gordon and Sirius Black are both played by the same guy. Also happened to Sirius satellite radio.
This meme has officially breached the political barrier, with various pictures of Barack Obama done up as The Joker ...and Sarah Palin, and John McCain, and Joe Biden...
It seems that everyone wants to show you a magic trick. Don't let them.
Various images involving Alfred's "Some men just want to watch the world burn" speech have characters doing things that aren't pure evil, just really, really stupid.
The Nightwing trailer for the game has "Trained by Batman" as part of his "Training" profile. The fandom has now taken "Trained by Batman" to automatically mean that the trainee is a badass.