I had written a roundly rejected magic item for a Pathfinder RPG contest some years back, and just stumbled across it again. For those of the game-nerding persuasion, have a look.
Tome of Deadly Pranks
Aura strong evocation; CL 17th
Slot - ; Weight 5 lbs.
This book looks exactly like a tome of understanding yet hides a powerful curse. Whenever the book is read, roll 1d10 on the following table to determine the result.
Every time the reader speaks the word, “Help,” in any language, she slips and falls prone.
The next item the reader touches shrinks as per the shrink item spell, except that the duration is permanent and the reader cannot expand the item.
The next member of the opposite sex the reader speaks to explodes, as if that person had just read explosive runes.
The reader can only verbally communicate in chicken clucks. He can still understand any languages he knows.
The reader's weight doubles, causing him to take a −2 penalty to Strength and Dexterity.
The reader, along with all her gear, is instantly transported to the nearest occupied bedroom.
The reader is polymorphed into a sheep.
Whenever the reader draws a weapon, that weapon shouts an embarrassing fact about that character's childhood.
A army of goblins declares war on the reader. This army is always within 20 miles of the party, and consists of any combination of gobliniods that add up to the party's ECL +2. The army tracks the party consistently and aggressively, yet non-magically.
Roll twice and keep both results.
All effects are permanent unless removed with a successful remove curse spell. Although Tomes of Deadly Pranks are created by error, many more are created by insidious Arcane Tricksters.