In Shakespeare's time, mattresses were secured on bed frames by ropes.
When you pulled on the ropes the mattress tightened, making the bed
firmer to sleep on. That's where the phrase, "goodnight, sleep tight"
came from.

At a book fair which I attended last week, I noticed that there were
many of my favorite books missing. I went up to the lady selling
classics and said, "What have you done with the medieval novels? Where's
Ivanhoe?"

Without missing a beat, she answered, "It's been banned from the fair!
There's too much Saxon violence!"

Young Kristin, the editor of our trivia publication, was having
trouble with her computer. So she called Wes, the computer guy,
over to her desk.
Wes clicked a couple buttons and solved the problem. As he was
walking away Kristin called after him, "So, what was wrong?"
And he replied, "It was an ID ten T error."
A puzzled expression ran riot over Kristin's face. "An ID ten T
error?" What's that in case I need to fix it again?"
He gave her a grin. "Haven't you ever seen an ID ten T error before?"
"No."
"Write it down," he said, "and I think you'll figure it out."
So she pulled out a piece of paper and marked down, I-D-one-zero-T,
and stared at it for a second while Wes beat a hasty retreat.
Needless to say he gave Kristin's desk a wide berth the rest of the day.