Call your boss and explain that you have an acute case of Tourette's and may breach the workplace harassment code if you come in.
Finish by calling him/her an "asswipe" or "jizzmonkey".
It's kinda the same as fake sneezing when you claim you've got a cold.
Yeah that works for me every time
Tell them a huge bee chased you down and stung you on the foot.
Just say you are lazy and dont really want a job.
That is ALWAYS a good excuse.
I'd go with the 24 hour Black Death bug.