Here's a game to try. You need a pair of dice to play. The object is to write a paragraph or short story using the dice to determine how many words to write per sentence. So, you roll the dice to get a total number, and then write a sentence in as many words as you rolled. (Roll a total of 6, write a sentence with 6 words. Roll a 9, write a sentence with 9 words, etc.) Stop when you've had enough, or after 15 minutes.
This is also a fun one to try in a group writing practice, or over coffee at the local caffeine joint. Extra points for most readable, or most weird. Winner gets chocolate!