Sure, maybe you played it in grade school. Foursquare was always popular in gym class when we were children.

Now it’s the latest craze in social media. As cell phones with GPS become more popular, new possibilities pop up — like Foursquare. This is an application for smart phones like your iPhone, Palm, BlackBerry or Android phone by “checking in,” you broadcast your location to your friends.

There’s a game element, too: you earn points whenever you check in. In fact, whoever visits a certain place the most becomes its “mayor,” and may be rewarded by a giveaway from that business. It’s already catching on with Pizza Hut which is giving away free breadsticks to the customer who becomes the “mayor” of an individual restaurant by checking in more times than anyone else.

Many are wondering why someone would do this. The answer is marketing and give-a-ways. Businesses can offer you free products as you walk by. And your friends can leave pointers about an establishment that appear right on your screen as you enter.

Right now, Foursquare has just shy of two million members, but it is growing.

Click here to sign up for a Foursquare account for free.