skivving........

An official word for “lying to take sick leave,” is called “Skivving”

It can be used at work, at school, when having to pay a family visit etc

Eskimos have, it is said, 200 words to describe the different types of snow. The British have a similar number to describe not going to work: pulling a sickie, swinging the lead, bunking off, having a duvet day, as well as the plain vanilla description: skiving

Some examples are :
"I need time to find myself"
"My garage door is broken"
"I'm going to jail"

Or, my personal favourite, "My partner and I need to practise for the square-dancing contest in town today"

Still in need of a good excuse ?   Check out the random excuse generator

Another definition that sounds like hard work : 

How to Skiv without Getting Caught

Skivving is the art of reading newspapers and other interesting things at work while looking like you're doing your job. Since reading is often more refreshing than a coffee break, it oughtn't be a crime to do. But lots of bosses think anything that's not work is waste. You gotta fool them.

And you gotta fool company spies. Rather than reading papers on line (and leave a record of your travels for the company to examine), cruise the newspapers and magazines at home. Copy the articles off, paste them into Word, and take them to work on a disk. When finished, move the articles off your hard drive and back onto the diskette. Take the diskette home to delete the articles. (Companies cruise what's been deleted first when they're checking up on you.)

Skivving is also a process used in shoe making !