I experienced my first World Cup Fever in 2010, while living in Switzerland. Coming from the United States, where football means shoulder pads and touchdowns, I had never paid one bit of attention to what the rest of the world calls football and we call soccer. And, as such, I didn't give the World Cup one bit of thought until the night that Switzerland upset Spain. While the game was playing, no cars were going up and down the street. The trams were running with just the driver and maybe two or three people. It was as if the entire world had shut down.

We live in an apartment building, and when something good would happen, we could hear a unified cheer through the building. We finally turned the game on, because we felt almost compelled to do so. The football fever didn't end when Switzerland lost; the people simply transferred their loyalty to their next favorite country. For most of our neighborhood, that was the German team.

Soccer is gaining popularity in the U.S. and for the 2014 World Cup, your business may have quite a few people who are as invested as my Swiss neighbors are. The World Cup lasts almost a month, so you can't, of course, just shut down and wait for it all to end. So, how do you make sure productivity remains high, even as the game is on?

Don't be punitive. The last thing you want to do is be that boss who screams, "Are you checking that score again!" and generally berating people. Look, it's important to people, and in the day of the smartphone, your employees will be checking the score. Don't threaten people with punishments for calling in sick to watch a game, and don't look to catch people goofing off.

Post the scores. If you have big fans, give someone the task of letting others know when someone scores and when a game has been won or lost. If they know that they'll find out when something important happens, it reduces the need to check the Internet every three minutes.

Be more flexible than usual. British employment consulting firm Acas  advises employers to allow employees to use flex days, swap shifts, or do any number of things that make employees' live a bit easier during the World Cup. But it also cautions against people using sick days, both to watch the games and because of hangovers.

Don't forget past performance. If your star performer is suddenly glued to the screen, gently nudge her back to work, but realize that this, too, shall pass. The last thing you want to do is drive a great performer out of your office because she's temporarily obsessed with soccer.

Watch select matches. One afternoon watching a big game will make your employees happy and not kill your productivity any worse than if they were surreptitiously trying to watch. Order pizza and soda (alcohol in the office is not generally a good idea, especially during the work day). Turn the television on. Even if the home team is winning, most employees will wander back to their desks and do work anyway.

Good performance is expected. Even though you don't want to be too uptight about the World Cup, you don't want to be too relaxed. It's still a business and you still have deadlines, clients, and important things to do.

Enforce your existing leave policies. Unless you want to make a blanket statement that you won't punish someone for calling in sick for a game, continue with whatever policy you have in place. If you require doctor's notes, continue to require doctor's notes. If you accept an employee's word (which is preferable for normal illnesses that don't require leave), accept the phone call that says, "I'm sick." You must trust your employees to be responsible. If not, you've got bigger issues than a loss of productivity.

You set the tone. The boss determines whether or not this a "fun" time or a "stressful" time. If you're positive but still hard working, your staff will follow your lead. If you're screaming at them, they'll be tense, angry, and watch anyway. And those feelings--be they positive or negative--will persist after the World Cup is over.