Sometimes you just need some time to yourself -- to hit a museum, get drunk in the afternoon or play Wii all night without the sound of your boss's voice ringing in your ears. But like a lot of Americans, you've only got 10 days of vacation a year, and they're already parceled out to family visits and your annual trip to Bonnaroo. Needless to say, those sick days start to look pretty tempting.

"Part of the problem of why we have to call in sick when we're not is that we don't really have the 'mental health day,'" says Lilit Marcus, Editor-in-Chief of SavetheAssistants.com, a Web site devoted to helping people navigate the unpleasant office environments where we spend a large portion of our lives.

"People work too much, our lives are stressful, and we need to take time off once in a while," says Marcus. "People burn out, and I think there's no shame in wanting to take a day off once in a while where you don't stare at your computer all day -- if you need to call in sick in order to do it, then so be it."

Click here for Marcus' foolproof tips for not raising suspicion when taking a sick day.

1. Always call your boss to tell them you're not coming in; never e-mail. "An e-mail just seems really fake," says Marcus. She notes that at some companies your boss might say, "Great: you're on e-mail. Just work from home today," which negates the purpose of taking your elective sick day. A telephone call comes off as a little more truthful and a little more urgent. When you call, try to time it so that you can leave a voicemail -- talking about the fact that you're sick opens it up to the possibility of follow-up questions and debate.

2. Don't be too specific. "Say 'I have a migrane' or 'I have food poisoning,' but don't go into details," says Marcus. "A lot of people get caught up in the details of the lie and feel like they have to specify what their symptoms are and such. But the more you talk, the faker it sounds. If you have the stomach flu, you're probably too busy barfing to answer a lot of questions about your condition."

3. Food poisoning is a good fake ailment. Marcus points out that "It's quick; it lasts a day; people get grossed out by it; and it's happened to them. So food poisoning is the way to go. Plus it's really non-specific. It doesn't say anything about a recurring condition that's going to happen again. It's a fluke. No one knows why it happened or what it was that they ate, so it's a really good mystery disease."

4. Don't post your exploits from your sick day on Facebook. Remember this story? Don't get caught in your lie by putting too much information where people can find it. "As people have things like more and more social networking sites, or you have a blog that people in your work know about, you need to be really really careful about indicting in any way what you were doing on your day off -- because you will get busted," says Marcus.

5. Don't come in with a sudden tan or a brand new wardrobe the next day. "Keep your head down and do your work," she says. "People are always a little skeptical, and you have to just pretend like you really were at home sleeping all day."

6. Pick a random Tuesday or Wednesday for your fake illness. At a lot of companies, there are mysterious sick waves on the day after a long weekend or on a really beautiful day in the summer. You can get away with that once in a while, but if you only come down with the flu on really beautiful Friday afternoons in the summer, everyone will be on to you. Taking off a day in the middle of the week will also make it less likely that you have 400 emails to sort through all at once when you come back from your elongated holiday.

Want to do something creative with your business cards on your day off? Check out business card origami below.