What Was Your Best April Fools Day Prank?

In the office? Around the house? What was your best April Fools Day Prank?

I look forward to this day every year and I am expected to do something (specifically around my office). However I have been unable to come up with something good. Just to give you an idea my last prank was tin-foiling a cubicle and before that I uploaded various hidden scripts that did things like make your desktop icons run away from the cursor when you went to click on them. Ideas please!?!?