A few weeks ago, we pointed to a popular list of 10 tips to do nothing at work. But sometimes it might just be easier to call in sick (or so we're told).
On those occasions, one can consult Call-in-Sick.com, a free service that sends in your sick call at a programmed time no matter where you are: "You stay out too late on a workday night and decide to call in sick the next day. The next day you drag yourself out of bed at 5am because you know your boss won't be there to answer the phone. With Call-in-Sick you can record your sick message the night before then schedule it to be sent directly to your boss's phone early in the morning without you even getting out of bed!"
And if you're too, er, fatigued to think of an excuse, you can always employ the Sickday Excuse Generator.