Good Office Prank:
My boss uses a lot of regular pencils. I got to work earlier than him and dipped each of his numerous pencil tips in clear nail polish. All morning I kept hearing his pencil sharpener as he grabbed a different pencil that would not write. He left the office for lunch so I re-dipped all of his pencil tips again. He finally figured out it was a prank about an hour before the end of the day -he thought it was classic!