Even if the Internet never comes up with another Fun Thing as good as the David Cameron poster creation machine, then it's nevertheless established its Daseinsberechtigung.
I mean, the original is humourous enough.
But the variations....
I'm quite fond of Cthulhu, Absorbency and...um...Kittens.
The following isn't nearly as funny, but it was the first thing that occurred to me.
Thanks to the Ranter for bringing this to my attention and for discussing it so (expectedly) well.