re: Best practical joke you've pulled at work

Around the 1990 I made a fake virus, just a little graphic program that I put in a co-worker's autoexec.bat file. I found out later that he had already been a victim of a real virus, so when he saw this, he completely fell for it. I was able to catch him turning on his computer, and I saw him silently staring at his screen, just steaming. After a few minutes I tried to explain that it was a joke, but it took several minutes for him to believe me. It worked better than expected!