I wrote a short story in which I gave myself a constraint: it had to be 26 paragraphs long, and the first sentence had to be _ is for ___ where the first blank was for a letter of the alphabet and the second one was for a word that began with the letter and had some (non-obvious) connection to the rest of the paragraph. It was way better received than I expected it to be, which is always lovely.
In other news, T is for Tuesday is for freedom.