According to a survey by Orbitz 1 in 5 workers lie to their employers saying they are sick so they can extend their weekend. Also that young whipper snappers, like me, ages 18-34 were more likely to do so.
Being I only have a total of 5 sick days for the year and no personal ones I have to be VERY careful as to how I use sick days. It really sticks when you have the flu and you have to go to work because you wasted your sick days earlier in the year. I can understand doing it though. Some times you just need a break from work, and if it means a three day weekend, even better. And if you plan well, it can be less painful for your co-workers. Not that I have ever done that. :-)