This one lurches towards the literary end of the bookshelf, but it can be a lot of fun.

Pick a scene, something simple. Two people having a romantic evening, and trying to scrape off the accidental tagalong. A job interview for professional base jumpers. Something that'll run itself, more or less. You're going to write it.

The trick is, you're not allowed to describe anything directly. Everything must be metaphor or simile. She did not have long black hair, but a mane of ink, or halo of midnight. A good rule of thumb:

• no colours that would normally be associated with whatever you're describing
• no adjectives or adverbs that would normally be associated with what you're describing (eg 'tall', 'blonde' or 'energetic' for people, 'shiny' for cars, etc)
• no nouns that are normally related to what you're describing (no 'hair', 'feet', 'lips', etc.)

It's tricky, and you're likely to wind up with something that reads like a Picasso, but I find it inspires a joyful silliness with language, and a great bout of creativity.

Feel free to get as purple as you like - amid the hilarity, you'll often find a gem of a description that'll shine when fitted into a more natural text.