My favourite...
When I was younger I tended to abuse my sickdays quite a bit. One day, late in the year, I called in at 7:00am to beg off my job at an office equipment dealer with vague complaints of intestinal distress and general offishness.

My usually-tolerant manager (a swell guy, really) told me that a couple of other slackers had already called in that morning and that he absolutely could not spare me as well, and I was going to have to suck it up and come in. He then added, ominously, "...and you'd better really be sick."

Crap! I was in a corner -- I had to go in to work and appear convincingly ill if I wanted to stay out of hot water.

So I took two tabs of blotter LSD, quickly dressed, and rushed out the door. By the time I got to work I was tripping pretty hard, but I did my job to the best of my ability, explained to those that I had to talk to that I was horribly ill and had a splitting headache, and tried to spend as much time as possible on quietly absorbing tasks like filing and setting up new machines.

I had a pleasant enough day, all considered, and in the afternoon when things were mellowing out, my boss (again, the best sort) came over, put his arm around me, and told me that he was really impressed with the effort that I put in despite how obviously sick I was, and let me know that it was appreciated.

--and I got the $200 "Employee of the Month" bonus that month for that little improvisation, too.
(Larry_Mudd, Mon 12 Jun 2006, 19:26, Reply)