1) To signal the end of a conversation, clamp your hands over your ears and grimace.
2) When someone hands you a piece of paper, finger it, and whisper huskily, "Mmmmmmm that feels soooooo good!"
3) While riding an elevator, gasp dramatically every time the doors open.
4) Babble incoherently at a fellow employee then ask, "Did you get all that, I don't want to have to repeat it".
5) For an hour, refer to everyone you speak to as "Bob".
6) In a meeting or crowded situation, slap your forehead repeatedly and mutter, "Shut up, PLEASE! All of you just shut up!"
7) Finish all your sentences with "in accordance with the prophecy”.
8) Put mosquito netting around your cubicle.
9) Walk into a very busy person's office and while they watch you with growing irritation, turn the light switch on and off 10 times.
10) Tell your boss, "It's not the voices in my head that bother me, it's the voices in your head that do."
I would like to add that I have personally tried a few of these and can testify that they do actually help alleviate office boredom.