Bet you didn't even know: If you use a cell phone for work (one provided by your company), you're supposed to keep a detailed log of every call you make on that phone, recording whether each call is for work or for personal use. If you don't, and even if 100 percent of the calls are for work purposes, your employer, by law, can't consider your phone a business expense. Instead, it has to consider the phone a perk provided by the company, which means its value has to be treated as taxable income to you.

If this sounds crazy it's because virtually no one follows the letter of the law on this issue. (If anyone out there has a work-provided cell phone and has the value of its service tacked on to their W-2 at the end of the year, let me know.) But it is the law, and it's basically remained unchanged since cell phone service began as an outrageous luxury for the rich in 1989.

While most employers have simply been ignoring the law—the same way that no one itemizes and pays taxes on out-of-state purchases—the IRS has of late been cracking down on the issue. According to the L.A. Times, UCLA got slapped with a $239,000 bill for back taxes because employees hadn't been keeping the aforementioned logs. UC San Diego received a similar, $186,000 bill. The University of California system provides some 13,000 workers with University-issued cell phones, so its potential liability is huge. Nationally, 5.5 million people have phones provided by their employers, which must have IRS agents' eyes lighting up with giant dollar signs like Scrooge McDuck.

The good news? Our Congressmen are trying to ride to the rescue to change the law that requires the absurd recordkeeping. Both the House and Senate have pending legislation to take cell phones off the list of taxable fringe benefits, and even the IRS' Advisory Committee now considers the rules to be overly "burdensome for any employer" and recommended relaxing the requirements.

See more details from the Times at the link below, including this gem of a quote from Texas Representative Sam Johnson: "In 1989 when cellphones were huge and when it cost a lot of money to make a phone call. Nowadays they're a dime a dozen and the cost is way down. If you don't log all your telephone calls, you're going to have some IRS weenie after you. That's why we're trying to get the law changed—because it just doesn't make any sense anymore."

LINK: IRS cellphone rule called outmoded