I was encouraging students to think of historical things they might know from 1750-1900 a couple of weeks ago. I reminded them of Charles Dickens to try to encourage them to think of hungry street urchins and workhouses.
I noticed this whilst wandering the classroom correcting spellings, but I couldn't trust myself to go in an correct it, so puerile was my humour at the time.
Also, this is probably the best student in the class. Her spider diagram was awesome. Why rain on that parade?