Recent studies find that your office coffee cup is the center of some major germ activity. 90% of mugs are covered in germs - 20% of which have traces of fecal matter.
Cleaning out your mug in the office kitchen does not count - those sponges and scrubbers are the main cause of your bacterial woes. Be sure to bring it home and wash it thoroughly in your dishwasher. Other objects in your office stuffed with germs?
Your phone, the photo copier, mouse, keyboard, fax machine - just about everything but the surface you might guess, the toilet seat.