Every year I make my freshman Bible class memorize the books of the Bible in order. The students hate this, but it usually turns into easy points on the final exam. One of my pet peeves is when people put an "s" on the end of the book of Revelation. I make this quite clear to my students, so they are careful to avoid it. What I now find amusing is that students get a little nervous about the "s" on the end of Revelation, and forget to put other s's on books where they actually do belong. Here are some examples from this year's crop.
The book of Psalm
The book of Lamentation
The book of Act
And in the reverse case
The book of first and second Samuels