This could be used any time you want the party to answer a riddle. I would recommend giving this to them in written form, so they can examine it visually, so that the answer becomes obvious after a while. This puzzle shouldn’t take long for any group of players to solve, but I found it interesting enough on it’s own to make a puzzle out of it.
Personally, I used this as a test of intellect for meeting with a very busy officiate. You see, he didn’t like dealing with stupid people, and this tended to clear out the riff raff.
This is a most unusual paragraph. How quickly can you find out what is so unusual about it? It looks so ordinary that you would think that nothing is wrong with it at all, and, in fact, nothing is. But it is unusual. Why? If you study it and think about it, you may find out, but I am not going to assist you in any way. You must do this job, though it is taxing, without any hints or coaching. No doubt, if you work at it for a bit, it will dawn on you. Who knows? So don’t act lazy for it will avail you nothing. Go to work and try your skill. Good luck!
The paragraph has no letter E.