Prompts should—

• be a short phrase or figure of speech;
• not lock participants into certain characters, settings, or plots; and
• be suitable for use as a title for the event; and therefore
• be in title case, using the following rules:
  1. the first and last words are capitalised;
  2. articles, coordinating conjunctions, and prepositions 4 letters or shorter are not capitalised;
  3. everything else is capitalised.